Journal of Civil Engineering and Architecture
Volume 9, Number 2, February 2015 (Serial Number 87)
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Journal of Civil Engineering
and Architecture
Volume 9, Number 2, February 2015 (Serial Number 87)
Contents
Architectural Research
121 Ambient Robotics for Meaningful Life of the Elderly Joohyun Chung
130 Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage Zoe Georgiadou, Dionisia Frangou and Dimitris Marnellos
141 Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran Arman Hashemi
153 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan Noriyoshi Yokoo, Tatsuo Oka, Keizo Yokoyama, Takao Sawachi and Makoto Yamamoto
165 Ornaments as Means of Efficient Reinforcement in Heritage Buildings Randa Hassan Mohamed and Abdu Wahab El-Khady
179 Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil Marcos Antonio Leite Frandoloso and Luciana Londero Brandli
188 A Review: Investigation of Bioplastics Ezgi Bezirhan Arikan and Havva Duygu Ozsoy
Structural Research
193 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building Abdul Aziz Ansari, Muhammad Aslam Bhutto, Nadeem-ul-Karim Bhatti and Rafique Ahmed Memon
207 Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand Sheets Bonded to Steel Beams Masatsugu Nagai, Yuya Hidekuma, Takeshi Miyashita, Yusuke Okuyama, Akiya Kudo and Akira Kobayashi
213 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures Nobuaki Otsuki, Akiyuki Shimizu and Toshiro Kamada
Transportation Research
225 Trends and Causes of Traffic Accidents in Dubai Akmal Abdelfatah, Mohamed Saif Al-Zaffin and Waleed Hijazi
232 Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation Fotis S. Mertzanis, Antonis Boutsakis, Ikaros-Georgios Kaparakis, Stergios Mavromatis and Basil Psarianos
Journal of Civil Engineering and Architecture 9 (2015) 121-129 doi: 10.17265/1934-7359/2015.02.001 D DAVID PUBLISHING
Ambient Robotics for Meaningful Life of the Elderly
Joohyun Chung Architectural Department, Seoul National University, Seoul 426-812, Korea
Abstract: It is innovative if people can be free from aged body and continue their career with assistance of robotics. It is supposed to see the change soon as smart phone changed life style. This research aims to figure out the direction of this change, development in technique for elders. It also studies various theories to justify various methods for ambient assistance robotic design for elders. In the long life expectancy world, this design will enhance the life quality of elders and encourage young people get pride in their own job, because their career will continue and it deserves to invest all their energy and sincerity in a specific area. As ambient robotics are a design for elders’ adjacent assistive design and part of everyday, it is related with quality of elders’ life. Some theories are cited for the importance of meaningful life. Meaningfulness is regarded as the fundamental goal of design purpose, because meaning stands upon the concept of human being and its consciousness activity. Phenomenological background of this research is introduced. It can be suggested in field observation to get real stories containing meanings and essence of life of elders. In conclusion, this study is a beginning of long process to prepare aging society with technique as well as perspective to see elders as valuable work force.
Key words: Aging society, meaningful life, phenomenology, ambient robotics.
1. Introduction for but also ones to live meaningfully and continue their career. It is not only the matter of self-realization We call aging society if the aging index is 7%. And and to keep human dignity, but also important human 14% is for the aged society. resources exclusion from society. Table 1 shows the ratio of the old over 65 years old In other aspects, elders who accumulated experience compared to the young under 14 years old. Some and wisdom should be used in society. Elders are a European and American countries began aging society group in a society who are usually retired from jobs early like 19th century and it took over a century or and have long experience as a social member. decades from aging society to aged one. But Japan and According to WHO (World Hospital Organization), Korea has the problem of shorter duration like 7 years people retire usually around between 50 and 60, and and 12 years. World is aging and soon become aged, life expectancy is 80 years. It means that they have but it is doubtful if aged people can contribute to the over 30 years’ experience and still around 20 years’ society and have proper self-respect. About life. It is regretful to hoard human resource uselessly employment ratio of age between 55 and 64 in leading for individual and for society. countries of the world shows 60% or 70%. A controversy about employment competition with If a man leaves his workplace around 50, it means the younger generation can happen. It is another that he is far away from society over 20 or 30 years. It challenge if the elderly still demonstrate their is so undesirable that someday he will be resigned and capability in the practical field, therefore, it should be his career will be stopped. It can be applied to various investigated in another paper. In this research, mainly careers, too. We work for 30 or 40 years and remain as the stance of elderly will get attention. a retiree for almost same years. The object of this study is to investigate the This work regards the elderly not only beings to care direction of the innovative development ambient
Corresponding author: Joohyun Chung, Dr., research fields: robotic design process for the elderly upon architectural planning and theory. E-mail: phenomenological perspective. This objectivity will [email protected].
122 Ambient Robotics for Meaningful Life of the Elderly
Table 1 Future population estimating [1]. Reached year Changed duration (year) Country 7% 14% 20% 7%→14% 14%→20% Korea 2000 2019 2026 19 7 Japan 1970 1994 2006 24 12 France 1861 1979 2020 115 41 Germany 1932 1972 2012 40 40 UK 1929 1976 2021 47 45 Italy 1927 1988 2007 61 19 USA 1942 2013 2028 71 15 fulfill the aim to show real object of ambient robotics, reach the balanced methodology of development. not only techniques but also contribution to desirable Literature investigation about life quality life quality. It is definitely the latest technique, which improvement and real good results will guarantee and is not only passive reaction to assist the weak physical elaborate all the ideas why we should reflect on the condition of the elderly, but also to figure out how the meaning of life and identity of elders. technique can contribute to human prestige. With the 2. Aging Society and Related Researches development of techniques like gene engineering, medical techniques and cut-edged telecommunication For this research, references for aging society, like smartphone and internet, life cycle becomes longer. academic journal, statistical analysis report and mass In addition, ambient robotics for aged people are one of media were reviewed. Mass media shows changed the rising issues for increasing the elderly: ambient attitude of elders who want to realize themselves, but it robotics are designed to help elders’ inconvenient is not easy to find academic researches about elders’ behavior in everyday life like shower and cooking. self-realization and career continuity. Healing Elders can enjoy self-regulating life, for example, they environment for the elderly is the main issue for the old. can also continue their professional career and achieve Pathological and sensual research is also one part of self-relization through work. It would be hopeful to assistive space design for the elderly. They insist on keep good condition with proper treatment like food preparing for aging-society and study about and exercise, and health investigation, but it would be gerontology or elders’ welfare. In short, to the most of so desirable also to get artificial assistance. experts, elders are weak beings who need care, not to Phenomenological reflection is one of main have self-determination. methodologies of this paper. Because technique To study about healing environment for elders is should not be developed alone, but it should be a part of very important for human right, like suggestions for whole life world changing. Life world is a concept passive green space, wandering areas for those with from phenomenology. Transcendental subjectivity of dementia and enough residence and community for phenomenology is the foundation of meaning owner. lonely elders. Some researches show the importance of meaning in Healing of elderly housing has objectives like the life, not only psychologically but also socially and physical stability and psychological stability. Moon [2] physically. Therefore, this paper supposes meaningful talks that human dignity is the most important healing life as an impetus for technical development. In other environment factors in health and welfare facilities. words, life cycle is getting longer, but we do not want Privacy can be the psychological factor to keep dignity. just longer life, but also valuable one. We need Environmental and social aspects require intimacy and quantitative methods as well as qualitative ones to familiarity. In terms of environmental and hygienic
Ambient Robotics for Meaningful Life of the Elderly 123 environment, good scenery, including the introduction of audio-visual art, is required. After all, these factors are associated with stress reduction. To design stress-free facility is absolutely important, but it might be possible to go further from passive reaction to active attempt, from not stressful space to self-realizing environment. Recently, neurologists also insist that elderly healthcare facility should have healing environment for immunology (psychoneuroimmunology) [3]. According to the study, the emotional stress will have an effect on the immune function of patients. German interior architect Monz [4] argued that the positive emotions can lead to improve the health of patients. There is another kind of research that does not remain in the passive reaction but goes further to face with enterprising spirit. Ambient robotics for elders is a case of good research to actualize meaningful life.
Fig. 1 shows the way to design ambient robotics. Fig. 1 Evaluation of the robotic furniture system by an age Georgoulas et al. [5] have researched and designed simulation suite. robots hidden in the familiar furniture. There are hidden sensors and telecommunication system directed to medical facility [5]. Yellow uniform has sensors in the red line and sends behavioral or physical change data to computer. Because it is hidden in furniture or combined to wall or door, there is no hindrance for every day but it assists weak physical function of elders. It is not to create new facility, but use existing furniture with cut-edged system. We can feel comfortable at familiar environment. This experiment is to match daily behavior to hidden sensors in furniture. Fig. 2 shows an example of innovative ambient Fig. 2 Functional transfer assistant [6]. robotics design, without mechanic and artificial occupation in room, elders can get help to move. A results. Another ambient assistance research is done or hanger is clung to ceiling and moves a man without still on progress by various categories like architectural space occupation. It is expected to reduce elements, elders’ behavior patterns and special inconvenient feeling by machine and we can regard us instrument development. as self-controlling beings, even though we are assisted Fig. 3 shows a kitchen modular design by cooking by instruments. process. Modular design is flexible and productive Figs. 1 and 2 are one of ambient assistance design [7]. Not only general adaptation with modular, but also
124 Ambient Robotics for Meaningful Life of the Elderly
Fixed installation tile, plumbing installation or water supply (sink, (dish-)washing machine, etc.) Rubik kitchen concept Semi-fixed installation tile, complicated but possible to move (integrated small electrical appliances, fridge, oven, etc.) Rubik kitchen concept
Flexible tile, independent movement (storage) Rubik kitchen concept
(a) (b) Fig. 3 (a) Cooking process experiment; (b) modular arrangement according to the process. special instrument can assist elders’ inconvenient solution. actions. When our physical ability is perfect, every Ambient robotics should not be understood as a process in kitchen is simple, but even a little weakness medium, because it is integrated into existing things, in a body reminds us that activities in kitchen are very and not perceptible part of everyday life. We cannot complex. Module is a tool to be flexible to apply to all perceive the being of the air, but we cannot live without moving and to modify systems according to each it. Ambient robotics also will not get our attention in individual. the life world like air. Because people have Fig. 4 shows another case of modular room but spiritual aspect as well as physical, for the real healing different from Fig. 3 [5]. All required functions such as beds, sofas, tables and chairs can be integrated into system, so the old can do various activities easily at one place. It is required to think differently when some activities become inconvenient when we get old. It does not mean that we became weak and handicapped, because a little design modification of living room and work room can enhance space usage ability. Sensors of Fig. 1 are also applied in the integrated furniture of Fig. 4. Fig. 5 shows an image of special bathtub for elders. Even young people can feel dizzy during hot water shower. If a man is slipped on the wet floor, it is so dangerous. This facility reduces any case of falling down, because the old can lean on the bathtub when it is not easy to stand for a while. A little gesture to put technical and mechanical protection eradicates accidents in a bathroom. Failure in basic activity in every day cannot disappoint anyone with this assistive Fig. 4 Proposed concept configurations.
Ambient Robotics for Meaningful Life of the Elderly 125
Fig. 5 Bathing assistive solution [8].
Employment ratio (%) (%) ratio Employment
Country Fig. 6 Employment ratio (%) of age between 55~64 [9]. environment for the seniors, the balance between countries except two are 60% or 50%. The elders are function and meaning should be kept and architectural usually long-trained so it would be wasteful to bury field should be developed based on the growth in their experience. There should be proper research technique and humanities. It is necessary not only to methodology to use latent and skilled professionals. think about how to develop techniques, but also to They do not need care facilities, but they need position reflect upon the reason why do we need ambient where their activity can gain recognition. This robotics and what do they mean to our lives. Reflection perspective is another perspective to bring elders a before big change by technique will guarantee us to healthier and dynamic life. It is not only for elders but save time and cost. also for next generation. A graph is composed to show employment ratio of When people look for jobs, they consider usually age between 55~64. Fig. 6 shows that considerable working period, retirement of their profession, and seniors between 55 and 64 are not employed: South high earning efficiency. Pension is the final hope of Korea and Denmark have over 70% ratio, but other desirable life in their old time. If work experience in
126 Ambient Robotics for Meaningful Life of the Elderly young age affects old age career, then work efficiency general formulation of the natural attitude to stop the of young people will also rise. Therefore, research to judge. In day-to-day life, we take the natural attitude. assist for elders’ vocational ability should be done. Although each individual experiences the world to be illusion or hallucination, even if that number is 3. Theoretical Background for Methodology revealed that even while maintaining the unity we 3.1 Life World believe to exist. The scope of the navigation is reduced through the reduction and exclusion. It does not We need to know the holistic meaning of a given preclude that determines what the problem is. surrounding. The perspective of aged individuals is In the radical developments of technique, we have essential in finding out what the holistic meaning of abundant data. Now, it is time to know the meaning of their surrounding is. The goal is to be able to observe a the change. Theoretical background provides situation without prejudice and develop the most researchers with the perspective and methodology appropriate method for analyzing these types of about how to approach to the problem. This research situations. Individual perspectives could be observed stands on the theoretical background of and interviewed, and this direct experience is belonged phenomenology. In phenomenology, transcendental to qualitative research comparing to quantitative one. subjectivity constitutes meaning in the life world. It For example, about statistics of birth rate and life takes time to constitute a meaning as it takes time to expectancy, we depend on quantitative analysis, but build a story or to go through a procedure. The story is ethnicity or national characteristics can be investigated made not only by causal relationship but also by by direct experience like observation and description. non-casual intentionality [10]. According to Husserl Life quality of the old cannot be explained only by [11], the meaning is noema and the intending meaning quantitative result: we need qualitative study about value, priority and justification in life. is noesis. This noesis can be meaningless but intuition Each person has different ways of remembering and is adequate to the noema. On the epistemological level, formulating their points of view. By using Husserl’s lived experience (erlebnis) is, in phenomenology, the phenomenological epoche and suspending our primary source of knowledge, but non-intuitional (e.g., tendency to form judgments, research can be scientific) perspectives as a part of the life world are established more clearly. He or she will compare also taken into account. previous analysis methods and develop various Life world is a concept from phenomenology. methods for organizing data. Having a flexible Technique should not be developed alone, but it should procedure based on sound experiential principles is an be a part of the whole life world changing. Then what essential phenomenological idea. Specialists in the can be the driving force for aging society? This paper humanities as well as medical technicians and nurses supposes meaningful life as an impetus for technical will participate in seminar discussions and otherwise development. We do not want just longevity, but also provide insightful feedback for the research. virtue in life. We can think with phenomenology and To receive the correct knowledge, a variety of means its methodology: qualitative methods like narrative, of communication is desirable. At the research scene, interview, observation or non-verbal methods like researchers need to be flexible in attitudes. They might sketches. be objective researchers as well as they should be On the ontological level, phenomenology daughter or friend of the elderly. This flexible attitude acknowledges the foundational character of the life gives us more clear essence. Phenomenological world. The concept of life world implies an reduction is achieved by stopping the judgment. This is epistemology in which the question of meaning is most
Ambient Robotics for Meaningful Life of the Elderly 127 important: the life world is the ultimate horizon for all construct stories as a way to understand life events. cognitive activities. As Husserl puts it, “The concrete According to Lee [12], the key to the solution of the life-world is the grounding soil of the ‘scientifically problem of truth is not the evidential experience, but true’ world and at the same time encompasses its own the communicative action. It is not the evidential universal concreteness” [12]. Heidegger [13] is a experience, but communicative rationality as the philosopher who tried to understand and explain formal pragmatic property of discourse that makes the human being. He analyses the meaning of dwelling in true claim of a statement acceptable. Lee [12] also relation to ontology. According to him, to be a human maintains that; since the constitution of a fact by an being means to be on the earth, in other words, they evidential experience is open to intersubjective dwell in the world. investigation, the intersubjective dimension of According to Sirowy [3], “phenomenology constitution is to clarify the condition of the possibility approaches philosophical inquiry from a different of that constitution. perspective, addressing the phenomenon of the world 3.2 Transcendental Subjectivity in terms of its being the determinate for the ontological meaning of all the entities within it, and not just Subjectivity in life world has various attitudes of something which is determined by them”. As religious, ethical, linguistic, social, economic, politic Heidegger [13] emphasizes, we always refer to things and anthropological. The subjectivity experiences as being “within the world”, and this indicates that we every day as well as something various. The have an intuitive understanding of the world, as coming experiences include emotional aspects like love, hate, before the notion of the things which are present within conflicts or sympathy. Life world subjectivity takes the it. We understand ourselves and things in terms of the general thesis of the natural attitude (generalthesis der world. The world, however, is not the ultimate frame natürlichen Einstellung). This attitude regards the within which everything is conceived, the world also world as the totality of what exists, and therefore there needs a human existence to perceive it. is nothing beyond the limits of the world. Phenomenology thus concedes that the “world” is, in However, there is something beyond life world like fact, also a part of dasein, human existence. The human atmosphere. Different atmosphere makes person world is always a lived world, a life world. Ontology experience something different: if we are depressed, and epistemology are closely interconnected in the we feel bored at everything, or if we are active, we feel phenomenological framework. As Heidegger [13] excited at everything. It means that the experience is maintains, “Ontology and epistemology are not two not fixed, but made for special meaning for subjectivity different disciplines which belong to philosophy by atmosphere. The subjectivity experiences the world among others. Both of them characterize philosophy as a part of it. Transcendental subjectivity is creative itself, its object and procedure”. and meaning creation flows endlessly. For instance, People cannot separate them from surrounding the experience in youth is different from that when we social system. Physical residence is for safety, and are grown up, because the meaning of each moment is self-respect and reason to live is given from social different. In conclusion, world of meaning is environment of relationship and participation in constituted by the transcendental subjectivity. society. Active job activities are needed for the This transcendental subjectivity is open to future and participation and a life story is a way to impose thrown away to next time. This subjectivity is called as meaning on life, thus connecting individuals to the existence in existential philosophy. Existo, the Latin event. McAdams [14] found that people tended to origin of existence is combination of ex and sisto: ex is
128 Ambient Robotics for Meaningful Life of the Elderly forward and sisto is to stand, therefore existo is to stand (human immunodeficiency virus) and witnessed the forward. Human being can be exposed as the entire death of a close friend from AIDS-related death. When structure of their overall appearance, while at the same confronted with the stress of such a death, those men, time, experienced as the life world subjectivity as well who were able to find meaning in the loss, were subject as transcendental subjectivity. to less rapid declines in CD4 T cell levels. Then, the subjects who experienced cognitive processing in 3.3 Meaningful Life response to the bereavement were more likely to find There is no doubt that humans are valuable, even meaning in the death of the close friend. Thus, in though they become old, they deserve worthy life. experiencing a stressful life event, if one is able to Worthy and meaningful life is one of human rights. engage successfully in finding meaning, there is a Meaningfulness is different from happiness as potential link to positive immunological benefits and Baumeister et al. [15] told in their paper. Happiness is health outcomes. fulfilled when needs are satisfied, but meaningfulness As there are benefits to making meaning out of life, can be made when personal identity and there is still no one definitive way in which one can self-expression are possible. According to Husserl [11], establish such a meaning. Those who were successful meaning is constituted in the life world by in creating a meaningful life enjoyed benefits such as transcendental subject. Meaning can be defined as the higher levels of positive effect, life satisfaction, etc. connection linking two presumably independent [19]. When faced with a stressful life situation, finding entities together. With the stated goal of positive meaning is shown to help adjustment [20]. psychology to foster thriving in individuals and render Meaningfulness in life is intrinsically related to a more fulfilling life, the interest of positive positive psychology’s goal to expand the good life for psychology is not to treat patients but to make a normal the normal non-disordered person. It is with a person’s life more fulfilling and for the non-disordered meaningful life that one is able to find connections to individual to flourish. people, places, and things. Currently, the meaningfulness theory supposes that meaningfulness is a subjective evaluation. Furthermore, 4. Conclusions meaningfulness is made through positive action, This study concerns with aging society and focus on satisfaction with life, the enjoyment of work, happiness, one of the ways to deal with aged society: technical positive affect and hope. Baumeister and Vohs [16] development of ambient robotics, artificial assistance also maintain that meaningfulness is fulfilled through for everyday activities and even professional works seeking four needs for meaning: sense of purpose, easier and self-esteem higher. Elders have relatively efficacy, value and a sense of positive self-worth. weak physical condition, need social welfare system Meaningful life affects even sickness. A study done and they should not be excluded from social relations. by Stillman et al. [17] found that social exclusion They are also unchangeable human beings who want to results in a perceived loss of meaningfulness in life. be recognized by other social members. When a man thinks himself to be socially excluded, Meaningfulness is one of essential elements of one’s sense of purpose, efficacy, value, and self-worth human beings. We do not need to answer only about are decreased. Bower et al. [18] found an association how to deal with aged society, but also why. This between the discovery of meaning and a lower rate of study finds theoretical background of meaningfulness. AIDS (acquired immune deficiency syndrome)-related The concept of life world and transcendental mortality. A study looked into a man who had HIV subjectivity are from phenomenology and become
Ambient Robotics for Meaningful Life of the Elderly 129 ideal foundation for meaningfulness. It is to reflect on Seoul National University Press. [11] Husserl, E. 1936. The Crisis of European Sciences and background of human beings who constitute meaning Transcendental Phenomenology: An Introduction to in life in the world. Phenomenological Philosophy. Seoul: Hangilsa. [12] Lee, J. 2004. The Crisis of Modern Life and the World: References Husserl’s Life-World Concept Study. Seoul: Dongnyeok. [1] Korean National Statistices Office. 2006. Future [13] Heidegger, M. 1971. Building Dwelling Thinking. New Population Estima. Korea: Korean National Statistices York: Harper & Row. Office. [14] McAdams, D. P. 1996. The Stories We Live by: Personal [2] Moon, C. 2002. The Role of Architecture for Healing Myths and the Making of the Self. New York: Guilford Environment. Korea: Yeonsei University. Press. [3] Sirowy, B. 2009. Phenomenological Concepts in [15] Baumeister, R. F., Vohsb, K. D., Aakerc, J. L., and Architecture: Towards a User-Oriented Practice. Oslo: Garbinskyc, E. N. 2013. “Some Key Differences between Arkitektur-og designhøgskolen (Architecture and Design a Happy Life and a Meaningful Life.” Positive Psychology College). 8 (6): 1-22. [4] Monz, A. 2001. Design als Therapie (Design as Therapy). [16] Baumeister, R. F., and Vohs, K. D. 2002. “The Pursuit of German: Alexander Koch. Meaningfulness in Life.” In Handbook of Positive [5] Georgoulas, C., Linner, T., and Bock, T. 2012. “Vision Psychology, edited by Snyder, C. R., and Lopez, S. J. Controlled Robotic Furniture System.” Gerontechnology Oxford: Oxford University Press, 608-18. 11 (2): 370. [17] Stillman, T. F., Baumeister, R. F., Lambert, N. M., [6] Georgoulas, C., Linner, T., and Bock, T. 2012. “A Crescioni, A. W., Dewall, C. N., and Fincham, F. D. 2009. Multi-robotic Assistant System (MRAS): A Development “Alone and without Purpose: Life Loses Meaning Approach with Application to the Ageing Society.” Following Social Exclusion.” Experimental Social Gerontechnology 11 (2): 381. Psychology 45 (4): 686-94. [7] Georgoulas, C., Linner, T., and Bock, T. 2012. “A Novel [18] Bower, J. E., Kemeny, M. E., Taylor, S. E., and Fahey, J. L. Mini on Agent Assisted Robotic Kitchen Platform.” 1998. “Cognitive Processing, Discovery of Meaning, CD4 Gerontechnology 11 (2): 369. Decline, and AIDS-Related Mortality among Bereaved [8] Bock, T., Georgoulas, C., and Linner, T. 2012. “Towards HIV-Seropositive Men.” Consulting and Clinical Robotic Assisted Hygienic Services: Concept for Psychology 66 (6): 979-86. Assisting and Automating Daily Activities in the [19] Davis, C. G., Nolen-Hoeksema, S., and Larson, J. 1998. Bathroom.” Gerontechnology 11 (2): 362. “Making Sense of Loss and Benefiting from the [9] Federal Reserve Bank of St.Louis. 2013. “Employed Experience: Two Construals of Meaning.” Personality Population: Aged 55-64: All Persons for Each Countries.” and Social Psychology 75 (2): 561-74. Accessed December 12, 2013. [20] James, J. M., Scanlan, M. P., Peter, P., Vitaliano, P. Z. J., http://research.stlouisfed.org/ fred2/series. Savage, M., and Ochs, H. D. 2001. “Lymphocyte [10] Lee, N. I. 2004. Phenomenology and Hermeneutics: Proliferation Is Associated with Gender, Caregiving, and Transcendental Phenomenology of Husserl and Psychosocial Variables in Older Adults.” Behavioral Hermeneutical Phenomenology of Heidegger. Seoul: Medicine 24 (6): 537-59.
Journal of Civil Engineering and Architecture 9 (2015) 130-140 doi: 10.17265/1934-7359/2015.02.002 D DAVID PUBLISHING
Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage
Zoe Georgiadou, Dionisia Frangou and Dimitris Marnellos Department of Interior Architecture, Decorative Arts and Design, Technological Educational Institution of Athens, Athens 12243, Greece
Abstract: In the early 1950s, the Greek National Tourism Organization made a nation-wide attempt to develop tourism in Greece. For a period of two decades, it developed the hotel buildings’ substructure, a project known as the “Xenia project”. During this period, Greek architects, devoted to modernism, designed and supervised 53 hotel compounds, which spread throughout the country. Today, the Xenia Hotels are internationally recognized as part of Greece’s modern cultural heritage, based on the simplicity, the definition of the form and the truth in materials use, besides the integration of the buildings in the natural environment, components which reveal themselves as a unique venture. This paper aims to reveal that, despite the efforts to retain the Xenia Hotels, these procedures remain incomplete. They rightly focus on architectural shells, morphological and functional standardization, proper utilization of the Greek environmental conditions, and the use of authentic local materials. However, the cultural evaluation of these settlements can only be completed by their holistic design, which also comprises their interior spaces, lightening and furniture design, all these detailed aspects that form an organic entirety and which are not included in these efforts.
Key words: Xenia Hotels, modern cultural heritage, holistic design, architectural approach, interior design, furniture design.
1. Introduction GNTO Council, which consisted of 10 members that specialized in tourism, exerted the tourism policies of The GNTO (Greek National Tourism Organization) the organization planned and executed within the in the early 1950s, within the national effort towards development of the Xenia Hotels project, connecting an economical reconstruction of the country after it with economy and qualitative tourism [1]. On a World War II and the Greek Civil War1, made a national level, this project defines the most important severe nation-wide attempt to develop tourism in attempt for mass production of public buildings, under Greece. The field of tourism had already been a state supervision and funding. The technical bureau of priority for the Greek economy since 1914, under the organization, staffed by trusted architects, different forms of state supervision and control2. The undertook the responsibility to organize and support the Xenia project by developing, for a period of about Corresponding author: Zoe Georgiadou, Ph.D., professor, research fields: architecture, interior architecture, sociology of two decades, the hotel building substructures in space, constructive and decorative materials, and space design. different “hoteling” types. The main goal of this E-mail: [email protected]. 1The Greek Civil War fought from 1943-1949, after World War project was the “creation of standards in hotel resorts”, II. built in Greek regions with exceptional natural beauty 2 1914 (Tourism Bureau), 1929 (Greek National Tourism and tourist interest, and insufficient or non-existent Organization in a primary form), 1936 (Sub-ministry of Press and Tourism), 1941 (Directory of Spa-Towns and Tourism), infrastructures. This project’s policy was meant “to 1945 (General Secretariat of Tourism), 1950 to today (Greek offer tourists accommodation in high class hotels, and National Tourism Organization), 2004 as part of the Ministry for Tourism Development, and from 2010, as part of the also to show private investors the aspired level of the Ministry of Culture and Tourism, recently from January 27, new hotel facilities that should be constructed in order 2015 as part of the Ministry of Education, Religion, Culture and Tourism. to develop tourism as the new profitable, financial
Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage 131 field in which the state aimed for”3. The decline of the Xenia Hotels came due to the During this period, starting from 1950 to 1957, turn to mass tourism, bad management, uncontrollable Charalampos Sfaellos as head of the organization’s and unregulated construction of new hotel compounds technical bureau and then Aris Konstantinidis from during the period of the military dictatorship in the 1957 to 1967, with a team of young Greek architects, years 1967-1974. The fact that Xenia Hotels are most of them devoted to modernism [2], such as Jason recognized as “building constructions that further the Triantafyllidis, Phillipos Vokos, Christos Bougatsos, development of architecture in Greece” according to Costas Kitsikis, Constantinos Stamatis, Dionisis Zivas, the theorist Panayiotis Michelis (1962) [3], which George Nikoletopoulos, Katerina Dialisma, Kleon consists of “the most important production of public Krantonellis, and also Dimitris Pikionis, designed and buildings in post-war Greece, achieving through the supervised, as technical bureau’s employees, 53 hotel integration of the settlements in the peculiar and compounds, motels and tourist pavilions 4 , which primeval Hellenic landscape, the establishment of a spread throughout Greek regions of the mainland and contemporary, pure, and sincere architectural the islands, with archaeological, topological or other expression, which interpreted the origins of touristic interest. modernism through a deep comprehension of the local The Xenia project was completed in 1974 and cultural references” [4], and that they are officially terminated in 1983. However, since 1970, characterized as “cultural heritage of the Greek and coming to a climax in 1980, many of these model European architecture of the 20th Century” [4], did hotel resorts started to decline, and were abandoned, not stop the disregard and the destruction of many of left void and unoccupied (Xenia of Andros island, them, in an environment where tourism policies do Florina, Nafplio, etc.). Some were demolished with not express anymore stable architectural objectives irregular procedures (Xenia of Chania, Heraklion, and vision6. Joannina), some were leased under unfavorable terms, 2. Architectural Characteristics of the Xenia without defining regulations for preservation, Hotels expansion and architectural interventions (Xenia of Poros island, Mykonos island, Mesologgi, Drama, Up to the 1950s, major hotel compounds were very Nafplio, etc.), some had their use changed (Xenia of few and situated in chosen, well known touristic sites. Delphi, Olympia, Volos, Rethymno, Igoumenitsa, etc.) The GNTO’s Management Council, of which two and the rest were transferred to the HRADF (Hellenic important and internationally recognized architects Republic Asset Development Fund)5 properties, and were members, Anastasios Orlandos and Periklis were divested for reducing the public debt Sakellarios, decided, within the frame of its new burden—Xenia of Paliouri Chalkidiki and Skiathos tourism policies, to assign the invention of new island have already been assigned since 2013. architectural standards for tourist accommodation to a selected team of architects.
3According to GNTO Council’S goals and objectives for Xenia The Xenia project, except for large hotel resorts, project. included many complementary programs for tourist 4The total number of the buildings produced within the Xenia project was about 70 (GNTO archives). pavilions, stations, motels, regeneration of spa-towns 5The Hellenic Republic Asset Development Fund was founded in 2011, with the mission to materialize a wide program for 6From an official letter written by the Administrative Council maximizing the proceeds of the Hellenic Republic from the of the Association of Greek Architects (Document No. development and sale of assets, in order to reduce the public 30517/11-6-2003) to the Ministry of Environment, Energy and debt burden. Referring to Xenia Hotels, this aims for money Climate Change, and the Ministry of Culture and Sports, for without considering rules or regulations for private investors in retaining the buildings of the Xenia project as modern cultural order to preserve and reuse the hotel compounds. heritage.
132 Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage and also for optional destinations sites of natural design fields in their chosen locations with beauty, with touristic interest in the mainland and the exceptional natural beauty, thus were recognized as islands, in areas that had not yet developed their landmarks, and also in the way they were embedded touristic substructures. The aim for building qualitative either into the natural or urban environment. Their hotel compounds in these areas was to attract high class harmonic integration in the ground’s curves with low international tourists. heights (one, two or rarely three floors), reveals the The organization’s orientation towards the creation adaptation to the human scale in most of the of architectural standards becomes clear both from the settlements. The utilization of natural local materials two eminent architects mentioned above [1], as well combined with modern ones (basically, concrete as from the creative team of young architects staffing without any plaster and metals) [6], as well as the the technical bureau who were well educated, most of study of the local traditional architecture, and the them devoted to modernism, and who worked under discussion about volumes and analogies, complete this the supervision of the inspired and experienced integrative procedure (Fig. 1). Sfaellos and Konstantinidis, heads of the bureau. The microclimate conditions define important Architectural options became one of the most serious design decisions, concerning the evaluation of the practices for the tourism policies of the organization. orientation (south or east for most of the openings, The architectural standards, which were developed north for cooling) for maximum benefit of solar through their work, were based on a solid theoretical penetration, wind cooling, etc., as well as the knowledge, also expressed in Konstantinidis’ writings. connection between the surrounding and the built These standards can be summarized as follows [5]: environment, through transitive enclosed open spaces, the importance of the location and land chosen which connect the inner and the outer space. As covering many of the design aspects, from the mentioned by Konstantinidis [6]: “let me see the way building’s scale, the microclimate components of the you build and I will tell you who you are. Not region—orientation, sun penetration, rainfalls, wind something entirely finished. Not something closed and fields and natural cooling, the local materials, also the unreachable. A place, where inner and outer spaces capacity of the building substructures to support the compose an organic entity. The interior space comes potential tourism development, as well as the local life and existing local culture; the sizes and standardization of the buildings as a whole, concerning their functional organization, their morphological and constructive rationality, always taking into consideration the local conditions, as well as individual parts of them, for example, the rooms; the holistic design, where the configuration of the surroundings, the building shells and the interior spaces, in all their details, structure a common unit, share the same minimal aesthetics and complete each other. Based on the above, the Xenia Hotels that were Fig. 1 Tourist’s pavilion of Chalkida. built, despite their different characteristics and the Source: Benaki Museum photographic archives, photo by uniqueness of each one of them, shared common Dimitrios Charisiadis.
Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage 133
Fig. 2 Xenia of Mykonos island (1960): bedrooms (architect: Aris Konstantinidis). Source: Projects + Buildings [7]. out to the open space. The outer space penetrates the bedrooms, with a clear flow of movement in the interior space. And they become one. All of us internal spaces, as well as in the surrounding area, participate in the same procedure. What is for the first closer and further [7]. The functional grid, which is also for the other—a construction with mental arises out of a simple architectural structure of typical content, for a common quota, for a widespread parts, is identified with the constructive grid, which is balance” and “so in the houses I have built… even in made of concrete without any plaster. The public all the Xenia, I have put in the right positions, one, or spaces are separated from the private rooms, often two or even more enclosed open spaces, which made with the use of transitive enclosed open spaces, as every building pleasantly ‘dwellable’. Because of mentioned above. The standardization is focused on these semi-enclosed spaces, these spaces that are in the basic repetitive module, which is the room, from between, between the inner and the outer spaces, give its construction to the furniture and lightening used, the opportunity to every human being to stand better aiming at saving money (Fig. 2). The projects have on his ‘dimensions’, to live in accordance with nature, detailed designs, and nothing is unintended—the opening a dialogic conversation, which will offer balconies, the windows, external louvers, the corridors, them so many pleasures and beauties” [6]. the cane sun screens [7]. The functional configuration is standardized with “And here I am, where I have been looking for the use of a wing’s system, especially for the ways to have standardization for the construction, and
134 Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage also for the functional configuration, thus each architecture, interior architecture, furniture design, architectural work not to be a unintended incident, but industrial design, etc., in this procedure7. This aspect to be a work of thought, something that aims for being prevailed in the work by many Greek architects during complete and perfect” [6]. the post-war period, including, Pikionis [9], These general characteristics are what built the Konstantinidis [10], Krantonellis [11] and others. vision of the Xenia project, which led to the major Pikionis in his work Xenia of Delphi (1955) [9], production of public buildings, during the post war which was designed with his colleague Papageorgiou, period. However, this architectural treasure, which is as well as Konstantinidis in Xenia of Andros (1958), internationally recognized as part of our modern Poros (1964) and Mykonos (1960) islands [10], was cultural heritage, based on the simplicity, the not only involved in the architectural design of the definition of the form and the truth in materials use, shell, but was also actively involved in the detailed and on the integration of the buildings in the natural design of the furniture pieces, the style of the interior environment, components which reveal them as a spaces and the color combinations used. unique venture [3], lies abandoned, time-destroyed, “The smallest detail and the general, total shape and void and unoccupied. Some of these settlements are size, should come out of the same spirit, in the same still in use, having undergone dramatic interventions sensation, through the same vein, for a minimal which altered their aesthetic meaning, while perfection. The walls, the ceilings, the casings (doors, extensions and adjuncts that have come about due to windows, dormer windows), the fireplaces, the closets, entrepreneurs’ occupancy have changed their earliest with them and the entire furniture, should have architectural inspiration [8]. common characteristics. As the same in nature, the trees, the bushes and the flowers compose a world with Thus, despite the national and international efforts the same essential core. And as everything, they taste mentioned above, mainly by the Association of Greek the same and talk the same language. Thus all the Architects, to retain the Xenia Hotels, these constructive elements coexist, so that if one of them is procedures should remain incomplete. They rightly missing, the other one is lost” [6]. The basic principles focus on architectural shells, morphological and established in the general synthesis concern minimal functional standardization, proper utilization of the forms, authentic local materials, colors and textures, as Greek environmental conditions, and the use of well as standardization, and are also the basic aspects authentic local materials. However, the cultural in the interior space design of the hotel resorts (Fig. 3). evaluation of these settlements can only be completed From the photographic archival material, we can by their holistic design, which also comprises their notice this perception of “decoration” 8 , not as a interior spaces, lightening and furniture design, all these detailed aspects that form an organic entirety 7 and are not included in these efforts. This paper Up to 1950, the common practice, with several exceptions, was for architects to complete their design, which included the suggests that this organic entity has to be treated as an architectural shells, as well as all the decorative elements of the unsegregated whole. project, furniture design and color, without any support from or co-operation with other specialties, such as interior designers, industrial and furniture designers, etc.. This was due to the fact 3. Holistic Design and the Interior Space of that these specialized areas were established during the following decades. Xenia Hotels 8Something that opened to international discussions, as in early 1910s, by A. Loos, Le Corbusier, P. Jeanneret, W. Gropius, etc., The significance of the organic entirety was a within an effort of disconnecting architecture from decoration widely accepted design concept, at least until the as a filler, and connected it with industrial production’s principles to a new aesthetic perception, with standardization as establishment of specialized areas, such as the main characteristic.
Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage 135 covering or incoherent concept, but as an integral contemporary artists of those years (Fig. 5). element of the architectural synthesis in accordance Generally, the forms of the furniture pieces are with the principles of the modern movement [12]. The geometrical, and wood is combined with leather and standardization of the equipment is achieved within textiles, which reveal their color and geometrical modernity, through functionality, the combination of forms. The special constructions, which are intended traditional and modern materials (usually wood and for public spaces, are completely integrated in them metals) and the aesthetics of industrial standards which prevail, whether they are common works (for example, furniture in the lines of Scandinavian design), or well recognized pieces (such as Barcelona by L. Mies Van der Rohe 1929, LC2, 3, the grand comfort armchairs by Le Corbusier, 1929, etc.). This aesthetics inspired Konstantinidis to design a series of standardized pieces of furniture for the bedrooms, armchairs for the public spaces and lamps for his Xenia Hotels [7] (Fig. 4). And this is not a separate design attitude as it was incorporated by other architects too, such as Triantafyllidis [13], who in the Fig. 3 Xenia of Mesologgi (1958): lobby (architect: Jason presentation of his work for Xenia of Nafplio referred Triantafyllidis). to the furniture he had designed, the textiles, the Source: Benaki Museum photographic archives, photo by lamps and the art works, which he had assigned to Dimitrios Charisiadis.
Fig. 4 Armchair and table design for Xenia Hotels, by Aris Konstandinidis. Source: Projects + Buildings [7].
136 Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage
motives, a variety of other designs can be seen. Lightening is a specific area of the interior architecture in Xenia Hotels. The recessed lightening is designed, integrated into the construction and structure of each place. In this way, the specific architectural elements (colors, textures, recesses, etc.) are emphasized. In the interior space, the lamps used, especially in the bedrooms, follow the design perspectives, and usually are placed on the walls, or standardized by the architect. Wherever the lamps are placed, they are usually made by a variety of materials, are simply formed and used to reveal the design’s Fig. 5 Xenia of Nafplio (1960): lobby (architect: Jason Triantafyllidis). aesthetics (Fig. 6). Source: Benaki Museum photographic archives, photo by Dimitrios Charisiadis. 4. Preservation of Modern Cultural Heritage
(bars, reception desks, shelves, closets, etc.). For the average tourists, as well as for the Greek Decorative motives on the furniture generally do not people, the historical periods that constitute the Greek exist, and in the few cases where we notice them, their cultural heritage are summarized to the wealthy presence is so small that it supports simplicity. Metal periods of the prehistoric and classical archaeology, the Roman and Byzantine archaeology, the local and wood details are used for the staircases, balconies, traditional anonymous architectural types, and the rails, dividing walls, etc.. neoclassical period which signals the establishment of The colors have a visual weight, fulfilling the the contemporary Greek state. The industrial building’s form, assuring the continuity of the inner revolution9 and, in particular, the modernism period and outer spaces, optically suiting the geometry of are not featured, among these widely acknowledged shape. Yellow ochre, terra-cotta red, black, plaster historical periods, as their built environment is less white, sky-blue and indigo blue, these are the ancient recognized, and mostly susceptible to interventions Greek colors, which are called by Konstantinidis that alter their main characteristics. “grounds” or “Polygnotia colors” [10], and are The political, social, demographic and economic combined with the natural color of materials such as changes in Greece, the recent rapid growth of the wood and stone. “Color in architecture is not a capital city, as well as the current developing decorative coating. Color in architecture works with economical crisis have changed the built environment, the constructive structure and is a valuable factor for and led to mass alterations into the urban space and making each built space an irreplaceable container of their surroundings. On the one side, an urban life. Because architecture is also made by color” [6]. transformation with the aim of modernizing cities Thus, the fabrics used on furniture pieces have the was supported by intensive erection, on the other side, color grade of the primary colors, usually in one color, and rarely in geometrical patterns with contrasts. The 9 During the last decade, certain cultural foundations have curtains were also designed using the same principles: supported the preservation of Greek industrial heritage, with emphasis on its artisanal and industrial technology, thus there were usually two—an airy fabric, combined with founding museums such as silk museum, olive and oil museum, a darker one. In rare cases, mostly in the public spaces, ceramic roof-tile and brickworks museum, etc.. Archives, educational and research activities have been established for wall patterns are used, where, besides geometrical this purpose on http://www.piop.gr/en/Foundation.aspx.
Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage 137
Fig. 6 Lamps in Xenia Hotels, designed by Aris Konstandinidis. Source: Projects + Buildings [7]. a common acknowledged basis was established, goal for this procedure should be connected with the concerning the preservation and conservation of the development of strategies and economical policies in architectural cultural heritage. The second aspect order to value and recognize this built treasure, referred to buildings belonging to the recognized keeping their characteristics and use connected to the historical periods, and some individual samples of competitive field of tourism development. modern buildings of the contemporary period [14, 15]. According to ICOMOS (International Council on However, the idea of “preserving the aesthetical Monuments and Sites)10 principles [17] for promoting meaning of each period, as it is represented at the and managing tourism in ways that respect and works left” [16] cannot leave aside contemporary enhance the heritage and living cultures of the host periods and monuments, where their “alive memory” communities, in order to encourage a dialogue and viability do not even require their use to be between conservation interests and the tourism changed, in order to preserve them. industry: “conservation should provide well-managed The Xenia Hotels, with their architectural opportunities for tourists and members of the host characteristics, belong to this category of buildings. community to experience and understand the local Thus, their preservation raises issues for identifying heritage and culture at first hand; the relationship the significance of this type of heritage, as well as between heritage places and tourism is dynamic and establishing criteria for their proposal and nomination for protection. Most of them are not yet nominated to 10ICOMOS was founded in 1965, in Paris by UNESCO (United be protected, although they are internationally Nations Educational Scientific and Cultural Organization), as a non-governmental international organization dedicated to the recognized as Greek modern cultural heritage. The conservation of the world’s monuments and sites.
138 Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage should be managed in a sustainable way for present assets in Greece should be recognized and connected and future generations; conservation and tourism with modern cultural heritage monuments and planning should create a visitor experience that is reinforce this period’s cultural routes, adding Xenia enjoyable, respectful, and educational; host Hotels as living and in use prevailed buildings, with communities and indigenous people should be positive consequences for tourism development. involved in planning for conservation and tourism; 5. Conclusions tourism and conservation activities should benefit the host community, improving development and Xenia Hotels are prominent examples of post war encouraging local employment; tourism programs public buildings in Greece. They represent an should protect and enhance natural and cultural important part of the cultural heritage of modern heritage characteristics”. And also in the ICOMOS Greek architecture, reflecting the vision of a team of Charter on Cultural Routes [18], the progression of architects and their innovating ideas for tourism ideas related to cultural properties is illustrated and development of the country, based on the ethical 11 the increasing significance of values related to their model of compensating hospitality . setting and territorial scale reveals the macrostructure The Greek state should retain this built treasure that of heritage. Objectives of the charter include: “to is the Xenia project as a part of the country’s history. establish basic principles and methods of research And this act should include all the morphological and specific to cultural routes as they relate to previously functional options and the vision of their designers: established categories of cultural heritage assets. To the shells, the inner and outer spaces with all their propose essential procedures for the development of matching components, which comprise them—stable, knowledge about the evaluation, protection, moveable, variable, each expressing its individual form and characteristics. Preservation cannot be preservation, management and conservation of conceived without considering the surroundings, the cultural routes. To define necessary guidelines, shells, the materials, the textures, the equipments, the principles, and criteria for correct use of cultural lightening as indelible parts of the design process. The routes as resources for sustainable social and lack of one of them disturbs the balance of the entity economic development, while simultaneously and distorts the holistic procedure of the design, as respecting their authenticity and integrity, appropriate well as the period expressed through it. preservation, and historical significance. To determine This is a fact noted in many cases: more often than the bases for national and international cooperation not, reconsidering the initial modern view led to a essential for research, conservation, and development deformed aesthetics of a new image. Modernization projects related to cultural routes”. does not mean the change of the synthetic components As been analyzed above, Xenia Hotels represent a but the conservation and maintenance of these holistic design approach, consisting of an organic characteristics that compose the general picture. “Each entity of the architectural shells into the natural material has its own voice and a low or high environment, the interior spaces, furniture, lightening, colors, textures in every detailed design. In the present 11The term is suggested by Panagiotis Ilias. According to Greek situation, some of them are abandoned, unoccupied, mythology, Xenios Zeus was as the god protector of the laws, time destroyed, demolished, or dramatically altered by also protector of the visitors asking for hospitality. This institution has been continued through the Greek tradition. A their new owners. Their preferential natural sites and premise for this is the mutual respect between the host and the cultural recognition could reveal them, as an attractive visitor. This term is connected with a tourism model that is based on equal respect and economical benefits for both sides, field for tourism development. These undervalued and not in the low side of money earning.
Xenia Hotels in Greece: A Holistic Approach to Modern Cultural Heritage 139 intonation. An architect knows how to reveal this The revitalization of the Xenia Hotels aims for voice and make it resound by agreeably matching sustainable tourism development and preservation of materials in a construction and placing them in their the remaining resources. It is also an opportunity to proper position. Composing his own music, the discuss and establish criteria and principles for architect enables his creation to speak and sing to us modern cultural heritage preservation, connected with and even offer us entire symphonies” [7]. their holistic design approach. Some people may think Analogically, every note should remain in place in that keeping them in the same original conditions this design symphony, contributing to the harmony of signals a space and time retreat. But as Chabbi and the sound. Mahdy [20] mentioned “in order to have a wide social The reused Xenia buildings have been dramatically impact, the preservation strategies should aim to altered, by their new entrepreneurs. In case studies [5], promote living in modern heritage buildings as an we mentioned that these alterations concern attractive option and promote the social status of occasionally either their architectural shell and residing or using modern heritage buildings”. Their surroundings, their interior architecture and decoration research refers to house heritage buildings, but it or all of them. In certain cases (Xenia of Poros, could also occur in hotel buildings of modern heritage. Mesologgi, Nafplio, Nafpaktos among others), new In this case, taking a vacation in a preserved, authentic, parts have been adapted, something that has ruined the modern hotel seams to represent an attractive option organic unity of the interior and exterior spaces, since and a motive for re-using the Xenia buildings. This the minimal and natural materials used, which were does not mean that someone has to refuse optically connected to the architectural shell and the contemporary comforts and achievements, and freeze surroundings, were replaced by others without the time in the 1960s or 1970s. This procedure represents same aesthetic quality. The refurbishments have taken a challenge for a different approach in the use of away the total identity of minimal and clear existing authentic substructures, considering style and morphology, as well as the truth of the constructive sense of the modern period. and decorative materials, that is to say, the main The same authentic design options in the Xenia Hotels also reveal among others an issue of moral design perspectives. Color as a component of nature: public architecture in contradiction to private environmental integration has been changed, without architecture, according to Konstantinidis [6], allows considering its initial sense. On the other hand, the for the transmission of authentic ideas and the interior spaces seem to be the most susceptible part of expression of a “true architecture”, which signals the new design choices and the easiest way to point moral attitude of the architect as a participant and towards aesthetic options that are however contrary to reflector of the social needs. Within the same morality, the original vision which established them as the Xenia project has defined the policy for tourism buildings of modern cultural heritage (for example, development, as a field for compensating hospitality, interior spaces in Xenia of Drama, Poros, Mesologgi, with the proper respect to the visitor. This policy etc.). Their interior spaces and original furniture have includes the built environment, not only as a been destroyed, or completely replaced, disrespecting profitable developing area, left adrift at the hands of the vision of their designers, as Konstantinidis private investors, but also as a procedure with rules, mentioned in one of his last interviews “the Xenia I boundaries and public control. have built are unrecognizable—the colors, the furniture everything has changed. And I began References wondering why?” [19]. [1] Moussa, M. 2012. “Xenia Project 1950-1967.
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Reapproaching the Role of Post-War Modern Grammata. Architecture in Greece.” In Proceedings of 1st [13] Hotel Xenia at Nauplia. “Archival Material 1961.” International Conference on Architecture and Urban Accessed January 13, 2012. http://issuu.com/ Design, 503-18. sxoliastis/docs/xenia?e=1023644/3199475. [2] Philippidis, D. 1984. Newhellenic Architecture: [14] Moschonas, N., and Kallivretakis, L. 1994. “Archaeology Architectural Theory and Practice (1830-1980) as of the City of Athens, Digital Edition.” Contemporary Reflection of the Ideological Options of the Newhellenic Monuments Database 1994.” The Substation of Public Culture. Athens: Melissa. Power Corporation in Athens, a work by Kleon [3] Association of Greek Architects. 2004. “Official Krantonellis (1971-1977). Accessed May 22, 1995. Nomination for Xenia Hotels by the Administrative http://www.eie.gr/archaeologia/gr/arxeio_more.aspx?id=45. Council of the Association of Greek Architects.” Journal [15] Moschonas, N., and Kallivretakis L. 1994. “Archaeology of the Association of Greek Architects 44: 20-2. of the City of Athens, Digital Edition.” Contemporary [4] Tzanavara, C. 2008. “Five Xenia Hotels Were Rescued. Monuments Database 1994. Round School by Takis The First Step Is Made.” Eleftherotypia Newspaper, Zenetos (1969-70). Accessed May 22, 1995. March 3. http://1gym-ag-dimitr.att.sch.gr/istoriko.htm. [5] Georgiadou, Z., Frangou, D., and Marnellos, D. 2014. [16] Zivas, D. 1997. The Monuments and the City. 2nd ed.. “Xenia Hotels in Greece: Rejection or Re-use? A Holistic Athens: Libro. Approach.” In Proceedings of the 4th International [17] ICOMOS. 1999. “International Cultural Tourism Charter: Conference on Tourism and Hospitality Management, Managing Tourism at Places of Heritage Significance.” 20-33. ICOMOS. Accessed October 25, 1999. [6] Konstantinidis, A. 1992. The Architecture of http://www.international.icomos.org/charters/tourism_e.p Architecture-Diary Notes. Athens: Agra. df. [7] Konstantinidis, A. 1981. Projects + Buildings. Athens: [18] ICOMOS. 2008. “The ICOMOS Charter for the Agra. Interpretation and Presentation of Cultural Heritage Sites.” [8] Georgiadou, Z., Frangou, D., and Marnellos, D. 2014. ICOMOS. Accessed October 4, 2008. http://icip.icomos. “Xenia Hotels in Greece: A Holistic Design Approach.” org/downloads/ICOMOS_Interpretation_Charter_ENG_0 Journal of Tourism Research. Accessed August 1, 2014. 4_10_08.pdf. http://jotr.eu/index.php/hospitality-management/83-xenia. [19] Themelis, K. 2000. The Speech of the Master: A [9] Pikionis, A. 1994. Dimitris Pikionis, 1887-1968. Athens: Conversation with A. Konstantinidis. Athens: Bastas-Plessas. Indiktos. [10] Konstantinidis, A. 1975. Elements for Self-cognition for a [20] Chabbi, A., and Mahdy, H. 2011. “Virtuous Circle or True Architecture. Athens: Ford Institution. Vicious Cycle? Modern Heritage and Development in [11] Kardamitsi-Adami, M. 2009. The Architect Kleon Abu Dhabi Heritage, Driver of Development.” In Krantonellis. Athens: Benaki Museum. Proceedings of 17th General Assembly, ICOMOS. [12] Vrychea, A. 2003. Habitation and Houses, Investigating Accessed August 1, 2014. http://openarchive.icomos. the Boundaries of Architecture. Athens: Ellinika org/1111/1/I-1-Article7_Chabbi_Mahdy.pdf.
Journal of Civil Engineering and Architecture 9 (2015) 141-152 doi: 10.17265/1934-7359/2015.02.003 D DAVID PUBLISHING
Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran
Arman Hashemi Centre for Sustainable Development, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
Abstract: Iran needs around 1.5 million residential homes to be constructed annually to answer its cumulative demand by 2025. Given the current situation of the Iranian construction industry, it seems almost impossible to achieve this objective by using traditional methods of construction alone. Offsite methods of construction can potentially increase the housing output in Iran thanks to their advantages over traditional methods. However, they cause a rather different set of risks which should be studied in the Iranian context. This study aims to investigate as to how ready the Iranian construction industry would be if offsite methods were to be introduced to the country in large industrial scales. To this end, a questionnaire survey was conducted to identify the risks and required actions in order to achieve successful application of these methods. Several subjects including costs, practicality, design and construction processes, demand, governmental policies, technology, and sustainability issues were investigated as the core research areas. The results revealed that, considering the current situations, it would be highly risky to introduce offsite methods of construction to Iran. Research findings highlight some key areas including design and construction processes, economies of scale, governmental supports, and education, which should be addressed to mitigate the identified risks.
Key words: Offsite construction, offsite manufacturing, prefabrication, construction technology, housing, Iranian construction industry.
Nomenclature Hybrid Also known as semi-volumetric system, hybrid systems system is a combination of volumetric/pod and Offsite “Offsite is a term used to describe spectrum of (semi-volu panel systems [1, 5, 6] construction applications where buildings, structures or parts metric) are manufactured and assembled remote from building site prior to installation in their final 1. Introduction position, in other words, moving operations that are traditionally completed onsite to a Iran needs over a million residential units (Fig. 1) to manufacturing environment” [1]. Offsite construction is also known as prefabrication, be constructed annually to answer its current housing modular construction, offsite manufacturing/ demand [7, 8]. In 2009, it was estimated that 24 assembly/production/fabrication, system building, and industrialized construction [2-5] million houses were required to be constructed in Iran Panel Panel systems comprise walls, floors and roofs by 2025 [9]. This means an annual output of 1.5 systems that are made from flat, pre-engineered panels and are assembled onsite in order to form a million residential homes during a period of 16 years. box/room [1, 5, 6] It seems almost impossible to achieve this objective Volumetric Also known as modular construction, volumetric systems systems comprise three-dimensional units which by using traditional methods of construction alone are completed in the factory and transported to (Fig. 2). For this and several other reasons, the Iranian the site to be assembled [1, 5, 6] Pods Prefabricated volumetric pod, fully factory Government has been trying to encourage the finished internally complete with building construction industry to increase the share of services. Examples include bath and kitchen pods [1, 5] innovative methods of construction to escalate the housing output.
Corresponding author: Arman Hashemi, Ph.D., research Many experts believe that the only solution for fields: architectural design/engineering, offsite construction and the current Iranian housing crisis is industrialization energy efficiency in building. E-mail: [email protected]. 142 Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran
Fig. 1 A view of Tehran from the northern mountains. Source: the author.
Fig. 2 Prevailing construction methods in Iran (Tehran). Source: the author.
[10-14]. This was, while in 2008, less than 3% of support this view [17, 18] and some disagree [19]. buildings that were built using industrial methods [15]. Some support the theory of offsite construction to The aim of the Iranian Government was to increase increase housing output in Iran [14-20] thanks to the the share of industrialized methods to 20% by the end advantages of offsite methods over traditional methods of the Fifth National Development Plan in 2013 of construction [1, 21-24]. Others believe that both [15, 16]. It was not clear as to what extent this modern and traditional sectors of the construction objective had been achieved. industry should develop more [25]. Various reasons, Yet, due to the geographical diversity of Iran and such as small scale of projects, market fluctuations, economic, cultural, and technical issues, heavy extra costs, and use of un-skilled labor, and limited industrialization is far from appropriate. Many studies knowledge of stakeholders about advantages,
Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran 143 disadvantages, and risks of such methods have been and construction processes when considering a method suggested as important barriers toward broader of construction. Six headings and 31 subheadings were application of innovative methods of construction in defined as the key criteria when considering a method Iran [17, 26]. of construction. This was based on the findings of the Some studies indicate that it may be necessary to available literature, similar questionnaires, including a alter the legislations [27, 28] and skill sets [12] to survey by the Commission for Architecture and Built introduce changes to the building industry. Other Environment [30], discussions, and interviews with studies argue that construction management is the Iranian and British architects. The identified criteria are major problem in Iran [29]. as follows: Much more in-depth research is required in the area (1) cost issues: total costs; speed of construction; of construction industrialization in Iran as the available quality of products; size of projects; ease of future selling; literature in this area is very limited and Iran is project management during design and construction; currently relying on other countries’ research in this (2) practicality issues: previous experience; skilled field. To this end, a questionnaire was designed to labor requirement; machinery availability; availability evaluate the current situation of offsite methods and the of details/information; availability of experienced level of knowledge and attitudes of Iranian architects contractors; availability of products in the market; (as one of the key stakeholders) toward such methods climate/weather dependency; ease of construction (e.g., of construction. The ultimate objective is to investigate less complex details); as to how ready Iranian architects would be if offsite (3) design issues: design quality; flexibility; cultural methods were to be introduced in large industrial scales issues/social acceptance; client preferences; aesthetic to Iran. In other words, the questionnaire has been matters; designed to undertake a risk assessment to evaluate and (4) technical issues: sound resistance; U-value; identify the required actions in order to have successful contract type; resistance in natural disasters (e.g., application of offsite methods of construction in Iran. earthquake); The results reveal several important issues which (5) governmental issues: planning/building approval; should be considered prior to any attempts to governmental supports; insurance; mortgage; introducing offsite method of construction to Iran. (6) sustainability issues: environmental issues; location of projects; health and safety. 2. Methodology It should be noted that these categories are not fixed This study reports on the results of a questionnaire and many of the factors above are related and designed to investigate the current situation of offsite interchangeable. Such relations were not revealed in construction in Iran. The questionnaire was distributed the questionnaire to avoid any in Tehran, capital city of Iran. Architects were pre-judgment/assumptions by the respondents. A major considered as the target research groups given their problem, which was discovered during the piloting high influence on design and selection of construction process [31, 32], was difficulties in clarifying the methods in Iran. The design, distribution, and meaning of offsite methods of construction to the analyzing processes of the questionnaire are explained research group. Therefore, a short description of offsite in the followings sections. methods was included at the beginning of the questionnaire to clarify the meaning and types of 2.1 Questionnaire Objectives and Design offsite methods of construction. Several criteria are involved throughout the design For the purpose of attitude scaling, Likert scales
144 Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran were considered [31, 33]. Some filter questions [32] questionnaire analysis. Sections A, B and C of the were also considered to split the respondents into two questionnaire deal with the current situation of the main groups of those who were and were not Iranian construction industry and evaluate the weight experienced in using offsite methods of construction. of the aforementioned criteria in decision making. The majority of the questions were in multiple choice Sections D, E and F examine the feasibility of applying and closed format [31-33]. Some control questions offsite methods of construction in Iran by studying the were also introduced to achieve reliable results. The attitudes of architects toward various design and questionnaire was divided into eight main sections and construction subjects. And finally, Sections G and H aimed to investigate two main subjects: study the personal attitudes of architects toward the current situation of the Iranian architectural different methods of construction. The ultimate profession with regards to knowledge of and objective is to find out the most influential issues, experience with offsite methods of construction; barriers, and risks when applying offsite methods of the real and perceived risks if offsite methods construction to Iran. were to be introduced in large scales to Iran. 3.1 Section A: Considering a Method of Construction 2.2 Questionnaire Distribution and Analysis According to the results, the most important factor The questionnaire was distributed among Iranian for Iranian architects when considering a method of architects working at consulting companies which were construction is the quality of products. This was selected randomly from registered architectural followed by the speed of construction and total costs as practices in Tehran. Thirty companies were visited and the second and third most important criteria (Fig. 3). 300 questionnaires were distributed from which about Three of the five most important criteria fall into the 100 returned and 88 were reliable. first category (cost issues) mentioned above. Around 40% of the respondents were very Also, the study reveals that the least important issues experienced architects with more than 10 years in for Iranian architects when considering a method of practice, 15% had 6~10 years, 32% had 3~5 years, and construction are in descending order: the rest had 1~2 years of experience. Respondents were ease of planning/building approval; fairly distributed with almost all ages from 20~25 to governmental support; 50+. Almost 47% of respondents were female and 53% mortgage matters. were male. 3.2 Section B: Why Offsite The results of the questionnaire were analyzed using SPSS (Statistical Package for the Social Sciences) and When it comes to offsite methods, it is obvious from Excel software programs. Since the data were nominal the results that speed of construction is the most and categorical, descriptive data analysis was applied important factor for those architects with previous using frequency and percentage. “Chi square” test was experience in using these methods. Around 91% of applied to examine the significance and reliability of respondents selected the higher speed of construction the results. The results in 94% of cases were as their most important criterion when considering statistically significant to P < 0.05 [31, 34]. The results offsite methods of construction (Fig. 4). presented in the text have been rounded to ±1%. The least important issues for Iranian architects when considering offsite methods of construction are: 3. Results less climate/weather dependent; This section reports on the results of the mortgage matters;
Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran 145
Aesthetic matters
Resistance in natural disasters
Total costs
Speed of construction
Quality of products
Fig. 3 Reasons for choosing a method of construction (%).
Size of project
Fig. 4 Reasons for choosing offsite methods (%).
governmental supports; This means that, apart from those who had never used cultural issues. offsite methods (about 44%), about 75% of the rest The study also reveals that most of Iranian architects were not experienced in any other offsite methods. (about 56%) are familiar with offsite methods. Almost Therefore, apart from panel systems, in total, about 100% of those who were experienced in offsite 86% of Iranian architects are not experienced in any methods had used panel systems and about 75% had other offsite methods. not used any other systems but panel systems (Fig. 5). About 91% of architects had applied offsite methods
146 Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran
Panel and other
Panel and hybrid
Panel and pod and hybrid
Panel and pods
Panel and volumetric and pods
Panel and volumetric
Panel
Fig. 5 Percentage of different offsite methods (%).
Lack of required details/information
Less speed of construction
More skilled labour requirements
Reduced design flexibility
Lack of offsite products in the market
Lack of experienced contractors
Lack of previous experience
Fig. 6 Main barriers for using offsite methods (%). in one to five projects from which more than 64% were systems. housing projects. Moreover, around 67% of those who 3.3 Section C: Why Not Offsite were experienced in offsite methods indicated that the approximate proportion of offsite products in their Section C mainly aimed to study the barriers toward housing projects was less than 25% in terms of applying offsite methods of construction in Iran. volume. Aboout 95% of prefabricated components used According to the results, the first three most important in housing projects were wall systems, 69% floor barriers for using offsite methods are the lack of and roof systems, 13% pods, and 0% volumetric previous experience, availability of experienced
Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran 147 contractors, and availability of offsite products in the The results indicate that 18% of architects ask for market (Fig. 6). Meanwhile, among those who had manufacturers’ advice in very early stages and about never used offsite methods, 100% indicated that they 94% consider manufacturers’ advice before the tender liked to apply such methods in their projects. stage. The results fluctuated when architects were asked about the time when they considered the 3.4 Section D: Construction Methods and Industry contractors’ advice. The figures indicate that 27% ask Relationships for contractors’ advice in very late stages during The aim of this section was to study the professional construction process on site and only around 5% relationships between Iranian architects and other consider their advice in the feasibility stage. According stakeholders in the construction industry. It also aimed to the results, most of the respondents (66%) consider to assess the decision making processes as to when and structural engineers’ advice in the planning stage while how architects considered a method of construction. only 7% consult structural engineers during the The results reveal that 58% of Iranian architects feasibility stage. consider the construction methods during the outline The results fluctuated again when architects were proposal and planning stage. Also, 23% think about the asked about the professional relationship between all construction methods in very early stages of design. All the bodies involved in the construction process. architects consider the construction methods prior to Around 10% of the respondents said that all or most of the tender stage. the stakeholders (clients, designers, engineers, When it comes to fixing/confirming a construction contractors, and manufacturers) met during the method, about 53% of respondents chose the third feasibility stage and around 29% mentioned that they stage of the construction process which is detailed met during the outline proposals. Around 64% proposals. Around 18% indicated that building believed that architects were the most influential methods changed even during construction on site people in terms of decision makings on the (Fig. 7). construction methods.
It changes even during construction
Construction stage
Tender stage
Detailed proposals (building regulations)
Outline proposals (planning stage)
Appraisal (feasibility stage)
Fig. 7 The stage when construction method is fixed (%).
148 Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran
3.5 Section E: Typical Housing Projects, Types and minor changes, 32% believed that there were some Sizes changes, and 12% said that there were considerable changes during the project. About 70% of architects Section E of the questionnaire intended to study the pointed that design changed even during construction current situation of housing projects in Tehran in terms process on site (Fig. 8). Architects indicated that the of suitability of sizes, types, and volumes for offsite majority of changes occurrred during the outline methods. proposals and detailed design. The study shows that around 80% of new housing Around 49% of the respondents believed that clients projects designed by architects in Tehran are apartment and about 35% said that structural engineers were blocks and the majority of them (about 43%) have responsible for the design changes. Architects took the 6~10 residential units. About 57% of these apartment blocks have 5~10 stories and 59% of the residential next place with about 33% of respondents selecting units have an area of more than 100 m2. Regarding them as the third group responsible for design changes. planning and building permissions, around 46% said Also according to the results, costs, client preferences, that planning permission process took around 2~4 and site issues had equal weights with around 27% of months for the majority of the projects. Around the respondents choosing them as the first common 28% said that the planning process would take even reason for design changes. longer. 3.7 Section G: Architects’ Views on Various 3.6 Section F: Design Changes Construction Methods and Products
One of the major criteria, which may increase the Section G aimed to study the architects’ ideas about risks of using offsite methods, is the design changes the current situation of the Iranian construction during the project [24]. This issue was studied in industry in terms of various construction methods and Section F of the questionnaire. the relevant issues to industrial Around 55% of architects indicated that there were production/manufacturing.
It changes even during construction
Construction stage
Tender stage
Detailed proposals (building regulations)
Outline proposals (planning stage)
Appraisal (feasibility stage)
Fig. 8 Construction stage when design is fixed (%).
Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran 149
According to the results, two third of Iranian was not a huge demand for offsite methods while 40% architects (66%) preferred more familiar and reliable mentioned that the current supply could not answer the methods of construction. Around 63% believed that demand. Almost all of the respondents (93%) indicated standardization would increase the design quality and that architects needed to know more about these 89% said that standardization would improve the methods. The respondents did not have a strong construction quality. opinion about building insurance and financial matters Around 37% of respondents preferred non-Iranian involved in applying offsite methods of construction. products, 20% preferred Iranian products, and the rest 4. Discussions mentioned that the source of products did not matter to them. More than half (53%) of architects indicated that The results of the questionnaire reveal several they believed that new construction methods were important issues which should be considered when more stylish and only around 6% disagreed. About applying offsite methods of construction in Iran. 64% indicated that Iranian people/clients preferred According to the results of Sections A and B of the modern looking buildings in which new methods and questionnaire, when considering any method of materials were applied. construction (regardless of being onsite or offsite), the quality of products, speed of construction, total costs 3.8 Section H: Architects’ Views on Offsite Methods of and aesthetic matters are the most important factors for Construction Iranian architects. This section intended to evaluate and review the Resistance against natural disasters such as architects’ opinions toward offsite methods of earthquake should be added to the above issues. construction in more detail. To achieve accurate results, According to the received feedbacks from the those who were not experienced in offsite methods respondents, the available offsite products in the were excluded from this section. market are too heavy decreasing the buildings’ Regarding the total costs of offsite methods, 38% resistance in the event of earthquake. Moreover, heavy believed that they were more expensive than products require stronger structure and more material conventional/traditional methods of construction and resulting in more waste and higher costs respectively. 28% disagreed. Around 51% of respondents indicated Therefore, the total weight of offsite products should that lifespan of offsite products were longer whereas be a concern when introducing these methods of 13% disagreed. Also, 60% believed that offsite construction to Iran. products/methods had higher quality. Results of Sections A and B also reveal that the Almost all architects (91%) believed that offsite Iranian Government has not been very successful in methods were faster than traditional methods of encouraging architects to use offsite methods since construction, which confirms the findings of Section B governmental issues are of less importance to of the questionnaire. Around 50% said that offsite architects. Three key facts may be deduced from the methods and products were more complicated to use, results of Sections B and C of the questionnaire: and about 67% indicated that more time was required First, Iranian architects need to be educated to in the design stage when applying offsite methods. know more about different offsite methods as they have About 73% mentioned that the society was showing very limited knowledge about these methods; more interest in offsite methods and 86% stated that Second, if adapted to the Iranian needs, panel such methods were becoming more common in the systems may be more successful in Iran since almost all construction industry. Besides, 49% believed that there architects have used, or are at least aware of them and
150 Offsite Manufacturing: A Survey on the Current Status and Risks of Offsite Construction in Iran therefore less effort may be required to to be successfully adopted and applied in Iran. educate/encourage them to use such methods; 5. Conclusions Third, considering the significantly higher importance of speed, quality, and costs to Iranian Several advantages have been claimed for offsite architects, who are highly influential in decision methods of construction including: improved speed; making processes, it would be more effective to focus improved quality; improved health and safety; on these factors when promoting offsite methods of improved control conditions; addressing skilled labor construction in Iran. shortage; not weather dependent; minimized waste and Project management is also a key element in energy consumption; enhanced value for money; and successful application of offsite methods of cost predictability. construction. Decisions should be made and fixed in Considering the significant housing shortages in Iran, early stages of a project [30] and designers and applying offsite methods of construction can manufacturers should be engaged in the process of potentially improve the current situation by increasing decision making to choose an appropriate system the housing output. The results of this study, however, [23, 30]. Late changes may also be too costly when it indicate that introducing offsite methods of comes to offsite methods of construction [20, 24]. construction in large industrial scales to Iran would be According to the results of Section D, Iranian architects too risky, given the current conditions of the Iranian are less aware of the correct process of applying offsite construction industry in general and architectural methods. Moreover, according to Section F, late design practices in particular. changes are a normal practice which considerably It should be noted that offsite methods are increases the associated risks of applying such methods considerably different from traditional methods of in Iran. This emphasizes the importance of educating construction in terms of the associated risks and architects, clients and other key stakeholders involved construction processes. Much more research is in the decision making process about the correct required on all abovementioned issues including costs, process of applying offsite methods and potential practicality, design, demand, policies, technology, and advantages and risks of these methods. sustainability issues to mitigate the associated risks in Continuing demand and economies of scale [35-37] order to have successful application of offsite methods are also some important issues which should be in Iran. Without considering such issues, not only considered when applying offsite methods. offsite methods fail to achieve their potential Considering the results of the questionnaire, the scale advantages over traditional methods, but also the of housing projects in Tehran/Iran should be current situation may even deteriorate. Yet, there are questioned since it may not be economically feasible to great opportunities for some offsite methods to be apply offsite methods in such small projects. successfully adopted if the mentioned issues are Moreover, long and unclear planning processes considered. To this end, the Iranian Government increase the risks of methods of manufacturing [24, 30]. should define a clear strategy to address the above The planning processes should therefore be reduced issues and provide support and incentives for broader and clarified to decrease the risks of application of application of offsite methods in Iran. these methods in Iran. Yet, the results of the 6. Further Research questionnaire indicate that Iranian architects have a very positive attitude toward offsite methods of This paper intended to identify the risks and construction, which is an opportunity for such methods opportunities if offsite methods were to be introduced
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Journal of Civil Engineering and Architecture 9 (2015) 153-164 doi: 10.17265/1934-7359/2015.02.004 D DAVID PUBLISHING
Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
Noriyoshi Yokoo1, Tatsuo Oka2, Keizo Yokoyama3, Takao Sawachi4 and Makoto Yamamoto5 1. Department of Design and Engineering for the Global Environment, Graduate School of Engineering, Utsunomiya University, Tochigi 321-8585, Japan 2. Utsunomiya University, Tochigi 321-8585, Japan 3. Department of Urban Design and Planning, Kogakuin University, Tokyo 163-8677, Japan 4. Housing Department, National Institute for Land and Infrastructure Management, Ministry of Land, Infrastructure, Transport and Tourism, Tsukuba 305-0802, Japan 5. Research and Development Center, Shinryo Corporation, Ibaraki 300-4247, Japan
Abstract: In July 2009, the 2005 basic Japanese input/output table was publicized together with its physical transaction table. This research paper analyzed the 2005 IO (input/output) table to create building industry-related intensities and, at the same time, compared the building industry with industries at large for distribution margins and transportation. The analysis of distribution margins separately for middle and purchaser margins found that middle margins in the building industry are minor at 35% of the averages for all industries, while purchaser margins are sizable at 1.8 times, proving that it is an industry for which local production for local consumption is quite effective. CO2 emissions resulting from transportation in the building industry were calculated and concisely characterized. Although the ratio of transportation CO2 emissions to total CO2 emissions in each industry finds almost no difference between general industries and the building industry, transportation CO2 emissions per production value are two to three times heavier than those from general industries to be justified as a transportation-intensive industry.
Key words: Embodied energy, embodied CO2, input and output table.
Nomenclature Embodied CO2 The sum of fuel related and non-fuel related CO2 emissions required directly Input and output The input/output tables are systematically and indirectly in all activities associated tables present and clarify all the economic with the provision of goods or service, activities being performed in a single including the amounts emitted in all country, showing how goods and services upstream processes produced by a certain industry in a given Energy intensity The total energy embodied, per unit of a year are distributed among the industry product. This paper applied to per itself, other industries, households, etc., consumer price of a product and presenting the results in a matrix CO2 intensity The total energy embodied, per unit of a format product. This paper applied to per Input and output The use of national economy and energy, consumer price of a product Margins Margins occurring when final construction analysis and CO2 data in a model to derive national materials are input into building sectors average embodied energy/CO2 data in a comprehensive framework and defined as purchaser margins in this Embodied energy The energy required directly and indirectly paper. Distribution margins are occurring in all activities associated with the among various industries resulting from provision of goods or service, including production together with purchaser the amounts consumed in all upstream margins. This paper defines these processes distribution margins as middle margins 1. Introduction Corresponding author: Noriyoshi Yokoo, Ph.D., associate professor, research fields: life cycle assessment, embodied In July 2009, the 2005 basic Japanese input/output energy/CO2, and energy efficiency of buildings. E-mail: [email protected]. 154 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
table was publicized together with its physical and reported CO2 emissions of imported woods transaction table [1]. This paper analyzes this IO products due to transportation occupy 30%-40 % of
(input/output) table and calculates CO2 emissions and total CO2 emission of wood products’ whole process fossil fuel consumption by industrial sector resulting from production process to construction site. Amano et from 1 million yen’s worth of production. The authors al. [6] conducted IO analysis and process analysis on analyzed every 5-year inter-industrial relationship up cement and concrete products, and reported that CO2 to 2000 from the 1960 input/output table and identified emissions due to transportation occupy about 12% of a change over the years in the intensities of carbon total CO2 emission of concrete products from dioxide [2, 3], thereby indicating that the reduction of production process and construction site. Yamabe et al.
CO2 emissions caused by construction is greatly [7] performed a simulation of circulation type of steel influenced by the intensities of carbon dioxide subject products in a society and showed that to a change in the entire industrial structure of Japan, 173,015~199,406 t-CO2 for transportation of 1,180,080 despite the indicated effectiveness of a design t steel products. contrivance. Thus, based on the idea that the latest Overseas, Cole [8] and Cole and Kerman [9] intensities are indispensable for design, this paper was calculated embodied CO2 by structure and determined brought to a conclusion. CO2 emissions per floor area from traffic resulting The 2005 IO table contains distribution margins by from construction. industrial sector to be input into the building sector In some other papers, CO2 emissions from (residential/wooden, residential/non-wooden, construction were successfully reduced by getting a non-residential/wooden, non-residential/non-wooden) little creative with the materials to be used [10-12]. that has not been conducted in previous IO tables. With Lenzen and Treloar [10] compared the analytical distribution margins considered as an issue directly results of inter-industrial relationships for embodied involved in local production for local consumption, energy in construction materials, analyzed the wood distribution margins and CO2 emissions resulting from and concrete designed buildings, and showed that the construction activities were collated. Since physical concrete-framed building causes higher CO2 emissions. transactions by industry from 1 million yen’s worth of Gonzalez and Navarro [11] showed the possibility of production are also contained in the data, it was reducing the CO2 emissions up to 30% in the determined that energy consumption and CO2 construction phase, through a careful selection of low emissions caused by construction could be calculated, environmental impact materials. Buchanan and Honey using producer’s and purchaser’s price-based type [12] compared several buildings and found that the intensities by business identified in this paper. modest change from concrete and steel to more wood In Japanese research papers concerning distribution construction could lead to a substantial reduction in margins of buildings, the energy used in the energy requirements and carbon dioxide emissions. transportation of materials such as steel, ready-mixed Studies about embodied CO2 are also published in concrete and wood has been reported [4-7]. Imada et al. volume abroad and they point out the importance of
[4] reviewed existing studied and inventory databases, quantifying CO2 emissions. Ramesha et al. [13] and summarized type of methodology of each database conducted a critical literature review of the life cycle to obtain energy consumption and CO2 emissions due energy analyses of buildings and summarized the to transportation process. Ikaga et al. [5] conducted a definition of embodied energy resulting from 73 cases survey on the imported wood products, and obtained across 13 countries, and showed that embodied energy
CO2 intensities due to wood products transportation, is 10%~20% of total energy of building life cycle.
Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan 155
Dixit et al. [14, 15] performed a review of literature consumption in industrial sector by the domestic output in the realm of embodied energy, identified parameters X and calculates the ultimate domestic output X causing variations in embodied energy data, and including propagation for the input of one million yen’s determined unresolved issues in existing international worth of domestic final demand. Assuming that LCA (life cycle assessment) standards. physical consumptions are proportional to the domestic output calculated, final physical consumptions were 2. Method of Calculation determined by multiplying transaction intensities with 2.1 Competitive Import-Type Matrix the domestic output. The value of X recalculated by applying final demand to Eq. (1) is compared with the This paper used the producer’s price-based domestic output contained in the original table, finding input/output Table S publicized by the Ministry of six highest-order digits identical and assuring the Internal Affairs and Communications. Basic Table S accuracy of the inverse matrix. has a 520 × 407 matrix and this was arranged into a 401 Energy consumption and CO emissions were also × 401 square matrix by consolidating column or row 2 calculated, using the fossil fuel consumption shown in items containing a business name different between the transaction table. Since oil products are imported in column and row items. Determining that the competitive measurable quantities, this paper used the fossil fuel import-type inverse matrix is common, such an inverse consumption in each industry shown in the transaction matrix is calculated, using the following equation: -1 table. But since crude oil is directly consumed for X = {I − (I − M)A} {(I – M)F(D) + F(E)} utility power and in part of the petrochemical industry, mi = Mi/Ci (1) crude oil is added to oil products for these industries. where: X: domestic output (yen/year); Assuming that CO2 emissions of 0.44 kg-CO2/kg is {I − (I − M)A}-1: Leontief competitive import-type derived from the consumption of limestone resulting inverse matrix (-); from cement manufacturing, this amount was added. I: unit matrix (-); Energy consumption and CO2 emissions were determined by multiplying the heating value of fossil M: import coefficient diagonal matrix; fuel consumed within each industrial sector with the mi: import coefficient (-); intensities of carbon dioxide (Table 1). Mi: import price of i product (yen/year);
Ci: domestic demand for i product (yen/year); Table 1 Intensities of fossil fuel. A: activity (input coefficient) (-); Calorific value CO intensity Fossil fuel Unit 2 (MJ/unit) (kg-CO2/unit) F(D): domestic final demand value (yen/year); Coal kg 28.9 2.506 F : import value (yen/year). (E) Crude oil L 38.2 2.613 In the calculation of Eq. (1), a Leontief inverse Natural gas m3 40.9 2.020 matrix is calculated to determine the ultimate domestic Gasoline L 34.6 2.322 output X including propagation by giving the domestic Jet fuel L 36.7 2.463 Kerosene L 36.7 2.492 final demand value. Light oil L 38.2 2.624 A heavy oil L 39.1 2710 2.2 Determination of CO2 Emissions Intensities B/C heavy oil L 41.1 2.922 In the transaction table, the physical consumptions Naphtha L 34.1 2.271 LPG (liquefied kg 50.2 3.002 and prices for 134 items are given for each industrial petroleum gas) sector. This paper prepares physical consumption Coke kg 30.1 3.251 intensities beforehand by dividing physical Limestone kg - 0.440
156 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
3. Intensity Tables of Energy Consumption residential/non-wooden, non-residential/wooden and and CO2 Emissions non-residential/non-wooden sectors, respectively. The purchaser’s price-based intensities shown in Table 2 3.1 Intensity Table are each expressed as a weighted average value of Table 2 shows the calculated intensities. Distribution distribution margins to be input into margins are defined as wholesale + retail + railway + residential/wooden, residential/non-wooden, road + coast + port + aviation + consigned forwarding non-residential/ wooden, and + warehouse. Among them, railway is freight non-residential/non-wooden sectors. For products not excluding passengers, and road is freight excluding to be input into construction such as rice, the average personal use. Input/output tables from 2005 and later values of distribution margins input into all industrial contain distribution margins of those products by sectors are used. Although the purchaser’s price-based industry to be input into residential/wooden, intensities differ in value depending upon the industrial
Table 2 Energy intensities and CO2 intensities by 2005 IO table in Japan, selected from 401. Energy per Quantity of material CO per consumer consumer price of 2 for consumer price No. Re1 Re2 Industrial sector price of million yen million yen of million yen (kg-CO ) (MJ) 2 (unit/million yen) 31 * Crushed stones 52,030 3,640 593.1 t 32 Other non-metallic ores 5,627 400 - 79 * Carpets and floor mats 33,507 2,364 - 80 Fabricated textiles for medical use 27,753 1,958 - 81 * Other fabricated textile products 41,221 2,882 - 86 * Other ready-made textile products 19,863 1,407 - 87 * * Timber 13,621 952 22.68 m3 88 * * Plywood 22,697 1,599 7.0 m3 89 * Wooden chips 8,619 604 99.01 m3 91 * Wooden furniture and fixtures 18,484 1,319 - 92 * Wooden fixtures 20,519 1,467 - 93 * Metallic furniture and fixtures 27,395 2,169 - 95 * Foreign paper and Japanese paper 73,672 5,804 - 96 * Paperboard 70,834 5,471 12.62 t 97 * Corrugated cardboard 50,211 3,795 16,620 m2 98 * Coated paper and building (construction) paper 40,538 2,976 - 102 * Other pulp, paper and processed paper products 33,237 2,453 - 135 * Petroleum Refinery product 12,497 882 - 137 * Paving materials 25,269 1,813 - 138 * Plastic products 56,893 3,971 - 142 * Other rubber products 40,109 2,836 - 146 * Sheet glass and safety glass 36,902 2,636 - 147 * Glass fiber and glass fiber products 71,691 4,842 - 148 * Other glass products 49,832 3,265 - 149 * Cement 315,036 80,992 124.4 t 150 * Ready mixed concrete 81,093 16,745 62.60 m3 151 * Cement products 43,193 5,994 - 152 * Ceramic 54,376 3,500 - 153 * Refactory product 42,661 3,220 - 154 * Other construction clay products 77,937 5,751 -
Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan 157
(Table 2 continued) Energy per Quantity of material CO per consumer consumer price of 2 for consumer price No. Re1 Re2 Industrial sector price of million yen million yen of million yen (kg-CO ) (MJ) 2 (unit/million yen) 155 Carbon and graphite products 62,870 4,832 - 157 * Miscellaneous ceramic, stone and clay products 40,091 3,259 - 160 Crude steel (converters) 394,408 39,897 21.45 t 161 Crude steel (electric furnaces) 100,059 8,356 19.47 t 162 * Hot rolled steel 189,779 18,271 13.47 t 163 * Steel pipes and tubes 119,963 11,182 6.158 t 164 * Cold finished steel 137,218 12,604 8.381 t 165 * Coated steel 90,489 7,958 9.002 t 166 * Cast and forged steel 95,785 8,400 2.374 t 167 * Cast iron pipes and tubes 102,598 8,701 8.061 t 168 Cast and forged materials (iron) 121,695 10,616 14.54 t 169 * Iron and steel shearing and slitting 106,916 9,838 - 170 * Other iron or steel products 56,294 5,062 - 171 Copper 22,906 1,745 2.072 t 172 * Lead and zinc (incorporated regenerated lead) 54,181 4,089 - 173 Aluminum (incorporated regenerated aluminum) 18,187 1,323 4.308 t 174 Other non ferrous cables 6,332 450 - 175 * * Electric wires and cables 22,562 1,611 0.645 conductor-t 176 * * Optical fiber cables 50,900 3,549 102.8 km core 177 * * Rolled and drawn copper and copper alloys 25,609 1,803 1.255 t 178 Rolled and drawn aluminum 22,112 1,576 1.766 t 181 * Other non ferrous metal products 15,913 1,139 - 182 * Metal products for construction 63,388 5,577 - 183 * Metal products for architecture 35,353 2,878 - Gas and oil appliances and heating and cooking 184 * 46,211 3,891 - apparatus 185 * Bolts, nuts, rivets and springs 45,000 3,859 - Plumber’s supplies, powder metallurgy products 187 * 31,310 2,515 - and tools 188 * Other metal products 34,987 2,855 - 189 * Boilers 22,980 1,832 - 190 * Turbines 25,190 2,062 - 191 Engines 29,550 2,408 - 192 * Conveyors 28,735 2,359 - 193 * Refrigerators and air conditioning apparatus 23,502 1,808 - 194 * Pumps and compressors 27,127 2,238 - 215 * Electric transformer 21,509 1,727 - 216 * Relay switches and switch boards 22,878 1,780 - 217 * Wiring device and supplies 15,198 1,128 - 221 * Electric measuring instruments 5,129 369 - 222 * Electric bulbs 24,101 1,670 - 223 * * Electric lighting fixtures and apparatus 24,345 1,770 284.3 p 224 * * Batteries 28,099 2,026 5091 p 225 * Other electrical devices and parts 19,045 1,355 - 226 * * Air conditioning equipment for consumer use 21,210 1,577 11.13 p Electric equipment for consumer use (ex., air 227 * * 19,780 1,498 24.80 p conditioning)
158 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
(Table 2 continued) Energy per Quantity of material CO per consumer consumer price of 2 for consumer price No. Re1 Re2 Industrial sector price of million yen million yen of million yen (kg-CO ) (MJ) 2 (unit/million yen) 228 * Video equipment 12,556 919 25.86 p 229 * Electric audio equipment 16,459 1,196 - 230 * Radio and television sets 15,340 1,105 6.900 p 231 * Wired communication equipment 16,467 1,194 - Radio communication equipment (ex., cell 233 * 20,529 1,471 - phone) 234 * Other communication equipment 18,928 1,366 235 * Personal computer 8,231 593 7.495 p 272 * Tatami (straw matting) and straw products 13,941 970 - 275 Recycle material recovery and process 38,981 2,753 - 276 * Residential construction (wooden) 19,921 1,707 6.318 m2 277 * Residential construction (non-wooden) 29,055 2,704 5.527 m2 278 * Non residential construction (wooden) 21,103 1,835 7.749 m2 279 * Non residential construction (non-wooden) 29,644 2,704 6.844 m2 280 * Repair of constructions 27,466 2,436 - 281 Public construction for roads 34,533 3,451 - Public construction for river, drainage and 282 31,684 3,333 - others 283 Agricultural public construction 40,215 3,919 - 284 Railway construction 36,907 3,650 - 285 Electric power facilities construction 30,751 2,800 - 286 Telecommunication facilities construction 30,105 2,449 - 287 Other civil engineering and construction 32,585 3,199 - 288 * Electricity supply 361,436 26,737 61.91 MWh 289 Self-power generation 297,811 19,695 116.9 MWh 290 * Gas supply 60,992 3,864 10,910 m3 291 * Steam and hot water supply 216,106 13,342 161.9 GJ 292 * Water supply 15,787 1,143 - 293 Industrial water supply 18,169 1,339 - 294 * Sewage disposal 112,135 8,130 - 295 * Waste disposal services (public) 44,332 3,155 - 296 * Waste disposal services (industrial) 26,296 1,880 - 306 * Railway transport (passengers) 27,661 2,070 - 307 * Railway transport (freight) 52,388 3,922 - 308 * Bus transport service 35,168 2,426 - 309 * Hired car and taxi transport 65,172 3,982 - 310 * Road freight transport service 690,696 47,728 - 311 * Transport by private cars (passengers) 133,960 8,964 - 312 * Transport by private cars (freight) 131,552 8,981 - 313 Ocean transport 693 50 - 314 * Coastal and inland water transport 2,156,033 154,125 - 315 * Port transport service 12,741 912 - 316 * Air transport 65,344 4,346 - Re1: industry sectors, which input four building sectors; Re2: based on domestic production output by industry section and product; *Quantity of materials for consumer price of million yen: gasoline 6.970 kL, jet fuel 16.67 kL, kerosene 14.84 kL, light oil 9.336 kL, A heavy oil 17.59 kL, B/C heavy oil 22.29 kL, naphtha 19.23 kL, LPG (liquefied petroleum gas) 14.22 kL.
Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan 159
sector into which such intensities are input, this paper, in 2005 were 8,356 kg-CO2 compared with 19,351 the target of which is buildings, prepared a purchaser’s kg-CO2 in 2000, while those from crude steel as a total price-based table of intensities to be input into the of Bessemer and electric steel in both years were building sector. In the case of transactions per million almost the same. This is probably because the method yen of the purchaser’s price, items contained in the of calculation in preparing the input/output table was table are limited in number and, therefore, domestic changed, resulting in much lower estimated CO2 outputs by sector and items are used in combination, emissions from recycled steel. thus identifying physical transaction intensities for a 3.2 Comparison with Japanese CO2 Emissions larger number of items.
Table 3 shows building areas and average building Fossil fuel consumption and CO2 emissions by costs in the building sector. The 2005 input/output industrial sector were configured per million yen of analysis identified CO2 emissions per million yen from domestic output and do not include propagation. These residential/wooden, residential/non-wooden, intensities were multiplied by domestic output (one non-residential/wooden, and million yen) and based on the transaction, fossil fuel non-residential/non-wooden as 1,707, 2,704, 1,835 and consumption and CO2 emissions resulting from final
2,704 kg-CO2, respectively, while the 2000 analysis demand (non-household, household) were added. had found about the same level of values of 1,725, Energy consumption was 15,018,450 TJ in the
2,514, 1,857, and 2,540 kg-CO2. Ready-mixed endogenous sector and 3,044,729 TJ of final demand, concrete discharged 16,745 kg-CO2 per million yen in while CO2 emissions were 1,099,538 thousand
2005, 9% more than the 15,192 kg-CO2 in 2000. tons-CO2 in the endogenous sector and 191,906
Hot-rolled steel released 18,271 kg-CO2 in 2005, 5% thousand tons-CO2 of final demand, totaling 1,291,444 more than the 17,451 kg-CO2 in 2000. Bessemer steel thousand tons-CO2. This was compared with existing emissions in 2005 were 39,897 kg-CO2 compared with materials concerning CO2 emissions in 2005,
28,550 kg-CO2 in 2000. Emissions from electric steel permitting us to consider that the total CO2 emissions
Table 3 Building floor area and construction cost. Industry sector Building type Floor area (m2) Building cost (million yen) Houses Houses 60,393,873 9,565,148 (wood) Houses with mix use 866,406 131,670 SRC (steel reinforced concrete) 2,446,919 431,110 RC (reinforced concrete) 28,761,927 5,090,743 Houses S (steel) 18,004,479 3,338,886 (non-wooden) Others 298,559 47,185 Houses with mix use 4,035,197 779,578 Non-residential Factory, storage 791,609 60,018 (wooden) Office, others 3,963,556 553,617 Factory, storage (SRC) 829,444 78,473 Office, others (SRC) 2,986,311 699,942 Factory, storage (RC) 1,219,598 138,911 Non-residential School (RC) 3,040,998 586,392 (non-wooden) Office, others (RC) 10,686,964 2,245,381 Factory, storage (S) 21,096,424 2,113,457 Office, school others (S) 33,083,100 4,796,792 Concrete block, others 407,231 58,055
160 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
in this paper are reasonable since the National Institute sector. These values are, if building sectors are targeted, for Environmental Studies gave 1,293,000 thousand of the margins occurring when final construction tons-CO2 [16] and the Greenhouse Gas Inventory materials are input into building sectors and defined as
Office published 1,287,000 thousand tons-CO2 [17]. purchaser margins in this paper. An appraisal of local production for local consumption requires the 3.3 Construction-Related CO2 Emissions evaluation of distribution margins occurring among Table 4 shows CO2 emissions in the various industries resulting from production together construction/civil engineering sector and CO2 with purchaser margins. This paper defines these emissions resulting from the operation of distribution margins as middle margins. If ready-mixed family-/business-purpose facilities. Compared with concrete is cited as an example, margins in the mining CO2 emissions in 2000 [3], it was found that the ratio of limestone and its carriage to a cement factory, and of CO emissions in the construction industry to those 2 then on the conveyance of cement to a ready-mixed from all of Japan decreased from 6.4% to 5.64% and, in concrete plant are defined as middle margins, and the case of civil engineering, such a ratio decreased margins in the carriage of ready-mixed concrete from from 8.0% to 6.11%. The operation of family-purpose the ready-mixed concrete plant to the construction site, facilities witnessed an increase from 12.7% to 13.96% as purchaser margins. and the operation of business-purpose facilities saw an increase from 15.0% to 18.43%. 4.2 Building Industry and Average Margins for All Industries 4. Analysis of Distribution Margins Table 5 shows CO emissions resulting from middle 4.1 Distribution Margins 2 margins and purchaser margins in residential/wooden, The 2005 IO table contains distribution margins by residential/non-wooden, non-residential/wooden, and industry on products to be input into each industrial non-residential/non-wooden buildings.
Table 4 CO2 emissions associated with buildings.
Industry CO2 emissions (1000 × t-CO2) Ratio (%) Wooden houses 16,552 1.28 Non-wooden houses 26,200 2.03 Buildings Wooden and non-residential 1,126 0.10 Non-wooden and non-residential 28,982 2.24 Sub total 72,860 5.64 Road 26,380 2.04 Civil works Others 52,537 4.07 Sub total 78,917 6.11 Coal 6 0.00 Kerosene 42,347 3.28 LPG 29,523 2.29 Operation of houses City gas 21,911 1.70 Electricity 86,453 6.69 Sub total 180,239 13.96 Transport of household 96,727 7.49 Operation of non-residential buildings 238,000 18.43 Total of Japan 1,291,444 100.00
Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan 161
Table 5 CO emissions of middle margins and purchaser 2 hinting at characteristically heavy CO2 emissions from margin associated with buildings. purchaser margins in carriage from each factory to the Middle margins Purchaser margins Industry sector construction site. The total of CO2 emissions resulting kg-CO2/million yen Wooden house 83.8 145.1 from middle and purchaser margins in building sectors Non-wooden house 89.3 132.1 amounts to some 70% of emissions for all industries,
Non-residential (wood) 79.5 124.3 finding a small ratio of CO2 emissions to the output. Non-residential 89.8 127.3 (non-wooden) 4.3 Comparison by Margin Type Average of all industrial 246.7 71.1 sector Figs. 1 and 2 compare breakdowns of CO2 emissions
Wooden house from middle margins and purchaser margins. CO2 emissions resulting from middle margins in the Non-residential non-wooden building industry are less than the averages of all million yen)
2 Average of all sector industries at 39% for wholesale, 7% for retail, and 48%
for goods transported by road. If CO2 emissions from purchaser margins are compared with the average values for all industries, wholesale is found to be twice emissions (kg-CO emissions 2
CO as large as the averages for all industries, while goods transported by road was about three times larger,
indicating particularly large values for roads. CO2 emissions resulting from middle margins in materials Fig. 1 Breakdown of CO2 emissions of middle margins. consumed in the building industry are minor, while
CO2 emissions from purchaser margins are heavy, Wooden house suggesting great effectiveness of local production for Non-residential non-wooden local consumption for the building industry.
million yen) Average of all 2 sector 5. CO2 Emissions Resulting from Transportation
5.1 Method of Calculation emissions (kg-CO emissions 2
CO CO2 emissions from transportation were calculated for comparison between those in the building industry
and other general industries. The CO2 emissions here were determined from values for freight traffic and Fig. 2 Breakdown of CO2 emissions of purchaser margins. passenger transportation to be input into transportation
The values shown in Table 5 are of ultimate CO2 sectors. These correspond to purchaser margins in the emissions including propagation as a result of 1 million industrial sectors in question and the transportation yen in input. If compared with the average values for corresponding to middle margins is not included. all industries, it is found that CO2 emissions from Transportation sectors relating to the middle margins in building sectors are scarce at some freights/passengers to be input into building industry
35% of all-industry average values while CO2 sectors are all included. The calculation used a method emissions from purchaser margins are about 1.8 times, of calculating the intensities of CO2 emissions in
162 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
transportation sectors (kg-CO2/million yen) tons-CO2, which is 2.1% less but determined as a beforehand for determination from the value input (1 roughly reasonable outcome. Calculation assuming million yen) into transportation sectors required by that the gasoline and light oil consumed in the family each construction sector. sector be spent for transportation identifies CO2 emissions resulting from transportation from the family 5.2 Calculation Results sector as 96,727 thousand tons-CO2, which accounts Tables 6 and 7 show the results of calculation. for 38% of transportation overall.
According to Japanese Road Policy Report [15], CO2 Table 6 shows the ratio of CO2 emissions in each emissions resulting from transportation in 2005 were transportation sector to total CO2 emissions occurring
260,000 thousand tons-CO2. In this paper, CO2 in each industrial sector. A comparison of all industries emissions from transportation total 254,417 thousand and the building industry finds almost no freight traffic,
Table 6 Ratio of CO2 emissions resulting from transportation. Building sector All industry Non-residential Non-residential Sector Wooden house Non-wooden house (wooden) (non-wooden)
Ratio of CO2 emissions (%) Passenger train 1.090 0.149 0.093 0.180 0.108 Freight train 0.043 0.012 0.007 0.012 0.007 Bus 0.283 0.072 0.036 0.033 0.020 Taxi 0.767 0.137 0.061 0.114 0.075 Goods transport by road 3.042 3.286 1.944 2.481 2.050 Passenger car 4.569 5.550 5.084 6.078 5.422 Truck 2.508 2.744 2.442 2.838 2.571 Coastal, inland transport 0.429 0.163 0.088 0.123 0.075 Port transport 0.065 0.021 0.011 0.017 0.009 Air transport 1.546 0.080 0.040 0.076 0.046 Sub total 14.342 12.214 9.806 11.952 10.383 Total of all sector 100.000 100.000 100.000 100.000 100.000
Total CO2 emission (t-CO2) 1,099,538,000 16,552,470 26,195,010 1,126,020 28,979,860
Table 7 CO2 emissions intensities resulting from transportation. Building sector All industry Non-residential Non-residential Sector Wooden house Non-wooden house (wooden) (non-wooden)
CO2 emissions (kg-CO2/million yen) Passenger train 0.811 0.254 0.252 0.330 0.293 Freight train 0.032 0.020 0.020 0.021 0.019 Bus 0.211 0.122 0.097 0.060 0.055 Taxi 0.571 0.233 0.166 0.209 0.204 Goods transport by road 2.263 5.609 5.257 4.553 5.543 Passenger car 3.399 9.474 13.748 11.154 14.662 Truck 1.866 4.684 6.603 5.208 6.952 Coastal, Inland transport 0.319 0.278 0.238 0.225 0.203 Port transport 0.049 0.036 0.029 0.031 0.025 Air transport 1.150 0.136 0.108 0.140 0.124 Sub total 10.671 20.846 26.518 21.931 28.080 Total of all sector 74.399 170.700 270.400 183.500 270.400 GDP (million Yen) 1,477,888,695 9,696,818 9,687,502 613,635 10,717,400
Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan 163
emissions in all industries are larger, although slightly, industries at large for distribution margins and except for wooden residential buildings. transportation. The results are summarized as follows:
Table 7 shows CO2 emissions corresponding to (1) A competitive import-type Leontief inverse domestic outputs by industry. Compared with the matrix was prepared and, in combination with the averages for all industries, the values of the building transaction, a method of calculation was given. Crude industry are larger by 2 to 2.5 times in goods oil consumption was not used, but physical transactions transported by road, 3 to 4 times in private of fossil fuel consumed in industrial sectors were used; transportation (passenger) and some 3 times in private (2) Energy consumption and CO2 emissions transportation (freight), indicating that it is the industry corresponding to 1 million yen’s worth of production for which CO2 emissions from transportation are heavy and purchase in each industry were listed in a table. for its output. Cole reported that CO2 emissions from Since from the 2005 IO table, distribution margins 2 material handling vary widely between 0.1 kg-CO2/m came to be shown by material to be input into the 2 and 1.0 kg-CO2/m from wooden buildings and building industry, purchaser margins targeting the 2 2 between about 1 kg-CO2/m and 6 kg-CO2/m from RC building industry were used; buildings [8]. The 2005 IO Table of Japan states 158 (3) An analysis of distribution margins separately for thousand yen/m2 for wooden exclusive residential middle and purchaser margins found that middle dwellings, 177 thousand yen/m2 for RC residential margins in the building industry are minor at 35% of dwellings and 234 thousand yen/m2 for SRC business the averages for all industries, while purchaser margins offices. If CO2 emissions resulting from material are sizable at 1.8 times, proving that it is an industry for handling are calculated from Table 6, 1.8, 2.3 and 3.1 which local production for local consumption is quite kg/m2 are obtained, respectively. From wooden effective; residential dwellings, Japanese CO2 emissions are (4) CO2 emissions resulting from transportation in heavy, but those from RC buildings are on a similar the building industry were calculated and concisely level to Canada. In Japan, there are studies about the characterized. Although the ratio of transportation CO2 energy used in the transportation of materials such as emissions to total CO2emissions in each industry finds steel materials and ready-mixed concrete, etc. [4-7], almost no difference between general industries and and studies are undertaken from the perspectives of the building industry, transportation CO2 emissions per local production for local consumption and the production value are 2 to 3 times heavier than those from general industries to be justified as a reduction of CO2 emissions from transportation. Some transportation-intensive industry. In the future, papers [18] on CO2 emissions associated with transportation across the building industry report that targeting actual buildings, we would like to propose emissions from wooden detached housing account for and evaluate a method of reducing CO2 emissions 3.4% of the total. resulting from construction. In this paper, the share of wooden residential References dwellings is calculated from Table 3 to give an almost [1] Ministry of Internal Affairs and Communications. 2009. identical 4.1%. 2005 Input and Output Table. Japan: Research Institute of Economy, Trade and Industry. 6. Conclusions [2] Kawazu, Y., Yokoo, N., Oka, T., and Ishikuro, H. 2008. “A Study on the Transition of Materials about the Energy This research paper analyzed the 2005 IO table to Consumption and CO2 Emission Associated with Building create building industry-related intensities and, at the Construction.” Journal of Environmental Engineering 73 same time, compared the building industry with (629): 931-38.
164 Embodied Energy and CO2 Associated with Buildings by Using Input and Output Table in Japan
[3] Yokoyama, K., Yokoo, N., and Oka, T. 2005. 249-55.
“Energy/CO2 Intensities Based on 2000 Input/Output [11] Gonzalez, M. J., and Navarro, J. G. 2006. “Assessment of
Table and Evaluation of Building.” Journal of the Decrease of CO2 Emissions in the Construction Field Environmental Engineering 589: 75-82. through the Selection of Materials, Practical Case Study [4] Imada, K., Nomura, Y., Ishikawa, T., Noda, C., and Hisaki, on Three Houses of Low Environmental Impact.” Building A. 2004. “Survey on Calculation of Environmental and Environment 41 (7) : 902-9. Burden of Wooden Houses Part1: Review of the Past [12] Buchanan, A. H., and Honey, B. G. 1994. “Energy and Studies on Calculation Method.” In Proceedings of Carbon Dioxide Implications of Building Construction.” Summaries of Technical Papers of Annual Meeting AIJ Energy and Buildings 20 (3): 205-17. (Architectural Institute of Japan), 1211-2. [13] Ramesha, T., Prakasha, R., and Shuklab, K. K. 2010. [5] Ikaga, T., Tsuda, K., Murakami, S., Kuma, K., Hondo, Y., “Life Cycle Energy Analysis of Buildings: An Overview.” and Narita, W. 2006. “Study on Life Cycle Assessment of Energy and Buildings 42 (10): 1592-600. Sustainable Buildings (Part 2), Comparison of [14] Dixit, M. K., Fernández-Solís, J. L., Lavy, S., and Culp, C. Environmental Impact of Local Woods and Imported H. 2010. “Identification of Parameters for Embodied Woods.” In Proceedings of Summaries of Technical Energy Measurement: A Literature Review.” Energy and Papers of Annual Meeting AIJ, 985-6. Buildings 42 (8): 1238-47. [6] Amano, K., Ito, M., Ikeda, K., and Yanagisawa, Y. 1996. [15] Dixit, M. K., Fernández-Solís, J. L., Lavy, S., and Culp, C. “Gross Resource Consumption in Relation to Cement and H. 2012. “Need for an Embodied Energy Measurement Concrete.” Environmental Systems Research 24: 425-9. Protocol for Buildings: A Review Paper.” Renewable and [7] Yamabe, Y., Tani, A., and Kawamura, H. 2008. Sustainable Energy Reviews 16 (6): 3730-43. “Simulation of a Reccurent Architecture Network Based [16] National Institute for Environmental Studies. 2009. Circulation Society.” Journal of Environmental Global Warming Gas Data in Japan. Japan: National Engineering 73 (624): 253-60. Institute for Environmental Studies. [8] Cole, R. J. 1999. “Energy and Greenhouse Gas Emissions [17] Ministry of Environment in Japan, Greenhouse Gas Associated with the Construction of Alternative Structural Inventory Office of Japan. 2009. National Green Systems.” Building and Environment 34 (3): 335-48. House Gas Inventory Report of Japan. Ministry of [9] Cole, R. J., and Kerman, P. C. 1996. “Life-Cycle Energy Environment in Japan, Greenhouse Gas Inventory Office Use in Office Building.” Building and Environment 31 (4): of Japan. 307-17. [18] Ministry of Land, Infrastructure and Transportation. 2005. [10] Lenzen, M., and Treloar, G. 2002. “Embodied Energy in Report of Road Policy for Prevention of Global Warming. Buildings: Wood Versus Concrete.” Energy Policy 30 (3): Ministry of Land, Infrastructure and Transportation.
Journal of Civil Engineering and Architecture 9 (2015) 165-178 doi: 10.17265/1934-7359/2015.02.005 D DAVID PUBLISHING
Ornaments as Means of Efficient Reinforcement in Heritage Buildings
Randa Hassan Mohamed1 and Abdu Wahab El-Khady2 1. Department of Architectural Engineering, the Higher Institute of Engineering, El Shorouk 002, Egypt 2. Department of Architectural Engineering, Collage of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Port Said 002, Egypt
Abstract: Heritage consists of those items people have inherited and want to keep, as they give them the sense of the past of their cultural identity, but these items, especially the buildings, could not face deteriorations during their period of life, such as the change of loads, the act of the environmental conditions, the effect of the duration time of the materials and the misuse of the occupants. They need special treatments and reinforcements to keep the structural state or to gain extra forces to receive the new loads. But the traditional ways of reinforcement do not prove endless solutions as the most means of the deteriorations from the nature. So, the liability issue is how to find the least reinforcement within the means of technology with the least deterioration and in a less time or by other ways efficiently. The hypothesis considers that the ornaments in some heritage buildings are found in critical levels of the construction which can share in an efficient way in the reinforcement processes of such buildings.
Key words: Ornaments, deterioration, heritage significance, efficient reinforcement, nano-materials.
1. Introduction heritage significance. So the paper will be divided into two parts to search Ornaments represent important items in heritage for the accuracy of such hypothesis as follows: buildings as they have the ability to demonstrate the (1) assessing the efficiency of the traditional ways of past: they represent means of the archaeological reinforcing the heritage elements of the buildings; remains which have special patterns of cultural history (2) assessing the role of the new technology in of local areas and they are important in demonstrating reinforcement and its relation to the ornaments. aesthetic characteristics and degree of creative or technical achievement in these areas. So they represent 2. Efficiency of the Traditional Ways of the real significance of the heritage buildings [1]. Reinforcing the Heritage Elements of the The ornaments vary from writings with especial Buildings kinds of art, fine gypsum patterns, fine timber details, Such part of the study will be divided into three part: crafts on masonries or special metallic ornaments. Also, redefining the efficiency of the heritage reinforcement, they are found in various positions in the heritage introducing the shapes of deterioration that need building as they spread in the outer envelope or in the reinforcement and finally assessing the efficiency of inner space. But using them in the proposed mission as the traditional ways of reinforcing the heritage means of reinforcement needs some studies to prove elements of the buildings. their effective share specially while using them within the new technologies which must not affect their 2.1 Redefining the Efficiency of the Heritage Reinforcement
Corresponding author: Randa Hassan Mohamed, Dr., associate professor, research fields: heritage and environmental In contrast to effectiveness, efficiency refers to the conservation. E-mail: [email protected].
166 Ornaments as Means of Efficient Reinforcement in Heritage Buildings cost as it means “doing the thing right” not doing the Relocation provides continuity of cultural right thing but this act opposes the constrains of the heritage value. A new site should provide a setting conservation of the heritage items as these items have compatible with cultural heritage value; to be treated in a sensitive manner as internationally. (2) The obscured items (the hidden items): the 1 The leading role in developing and promoting material of a particular period may be obscured or heritage conservation principles sets out some common removed if assessment shows that this would not principles that guide conservation work, as the key diminish the cultural heritage value of the place. In principle of conservation work is the importance of these circumstances, such material should be understanding the significance of a place before documented before it is obscured or removed; making any decisions about its future. Otherwise, the (3) The addition: the only change accepted heritage significance can be demolished [1, 2]. So concerned the installation of electricity, modern statutory heritage listing not only controls the plumbing and improved roofing, which were justified demolition of listed heritage items, but also limits the on the grounds that they help to protect the historical degree to which changes can be made to them. Also, remains and insure their future use. legislation requires owners to apply to a consent So the efficiency is always accompanied by the authority (the local council or the heritage council) significance of the heritage items. It must be achieved before making substantial alterations. And there are within effectiveness: doing the right thing with least many exemptions to this requirement for relatively money or in a sustainable manner. minor works or those that will have minimal effect on The most important goal is to obtain an end result the heritage significance of the place as the aim of the that approaches the original stone, brick or concrete as legislation is to achieve a sensible balance between identical as possible (color, texture, elasticity, porosity, retaining the heritage significance of special places and dilatation and shrinkage, etc.) and to limit possible enabling them to continue to be of use to the owners future side effects (chemical or mechanical). Selection and the community [3, 4]. of which type to use will depend on: And there are constrains for the change concerning compatibility of both materials (the existing stone the relocation, the removing or adding of the items as and the repair-mortar) in all regards; follows [1]: “treatability” of the work (geometrical or formal (1) Relocation, however, can be a legitimate part of complex) and the workability of the mortar (hardening the conservation process where assessment shows that: period/level of plasticity); The site is not of associated value as an work and climate conditions (inside, outside, exceptional circumstance; warm, humidity) [5]. Relocation is the only means of saving the structure; 2.2 Types of the Deterioration of the Elements That Need Reinforcement 1The leading role in developing and promoting heritage conservation principles has been taken by the ICOMOS (International Council on Monuments and Sites), a Most factors causing deteriorations to the elements non-governmental body formed in 1965 under the auspices of forming the buildings vary between humidity, the UNESCO (United Nations Educational, Scientific and Cultural Organization). As early as 1966, ICOMOS adopted a charter rising ground water table, the over loaded sewage for conservation work (known as the Venice Charter), which systems and the poor techniques used in the restoration set out internationally accepted conservation principles. Following the lead of the Venice Charter, the Burro Charter process that had its impact on the restored parts, but the (prepared by Australia ICOMOS), the New Zealand Committee deteriorations can be classified according to their of ICOMOS has adopted its own charter, the ICOMOS New Zealand Charter. seriousness as the inconsequential damage, the
Ornaments as Means of Efficient Reinforcement in Heritage Buildings 167 repairable damage and the overall repair or replacement [6]. 2.2.1 Inconsequential Damage Problems of this type are of no immediate structural concern, but they do need attention for the structure to maintain its durability. Examples of such damage are:
(1) decomposition of lime mortar between stone courses and between adjacent stone blocks in walls. This is probably due to loss of adhesion of the mortar to the adjoining stone over time, combined with some slight relative motion (Figs. 1-3); (2) partial wear of blocks made of friable or weak Fig. 1 The deterioration of the northern wall of al-Azhar Mosque due to the humidity and the wind factors in 1915 sandstone, mostly due to weathering (Fig. 4); [6]. (3) desiccation of new replacement stone blocks because of their poor quality and high porosity (Fig. 2);
(4) deterioration of stone and masonry blocks because of probable chemical aggression of gypsum plastering or air pollution; (5) old sporadic vertical fissures in thick stone walls (Fig. 5); (6) slight old separation at intersections of walls. For example, the deterioration of the northern wall of al-Azhar Mosque due to the humidity and the wind factors in 1915 is shown in Fig. 1. And another example: the lime stone blocks that rapidly deteriorated but marble blocks remain stable at al-Azhar Mosque in Fig. 2 Lime stone blocks are rapidly deteriorated but Cairo, Egypt in 1992 shown in Fig. 2 [6]. marble blocks remain stable at al-Azhar Mosque in Cairo, Also, the disintegration of lime stone caused by salt Egypt in 1992 [6]. deposits from ground water in al-Ghuri in Cairo, Egypt in 1992 (Fig. 3) [6], and the stone and masonry failure caused by the gypsum plastering were used for restoring the wall of Qawsun Gate (Fig. 4) [6]. 2.2.2 Repairable Damage In this category, damage or problems needs prompt action to avoid potential failure under any future overload or soil subsidence. Examples include: (1) disintegration of the lime mortar between stone blocks of arches and domes; (2) through cracks in stone blocks of lintels;
(3) continuous vertical separation between stone Fig. 3 Disintegration of lime stone caused by salt deposits blocks; from ground water in al-Ghuri in Cairo, Egypt in 1992 [6].
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(4) active settlement cracks at wall corner; (5) local failures in slender elements such as minaret marble columns; (6) disintegration of stones at wall intersections, for example, the local failure in a marble column in Sarghatmash mosque in Cairo, Egypt after the earthquake in 1992 [6]. 2.2.3 Overall Repair or Replacement In this category, structures or parts of structures have already collapsed, or where overall failure is imminent, such as: (1) severe thrust of domes or arches on abutments or Fig. 4 Stone and masonry failure caused by the gypsum plastering used for restoring the wall of Qawsun Gate [6]. walls; (2) excessive settlement that has distorted the structure; (3) tilting and/or displacement of wall corners due to excessive settlement; (4) disappearance of wooden floors or wall parts in areas where collapse has already taken place. Examples of such deterioration are: the collapse of the temper in house of Ali Katkuda after the earthquake in 1992 (Fig. 6) [6].
2.3 Assessing the Efficiency of the Traditional Ways of Reinforcing the Heritage Elements of the Buildings
There had been various aspects of reinforcement Fig. 5 Local failure in a marble column in Sarghatmash Mosque in Cairo, Egypt after the earthquake in 1992 [6]. applied on the heritage buildings especially in Egypt. Many of the techniques involved are no longer part of the modern construction industry vocabulary and others are as means of the revivalism of the heritage traditional one. 2.3.1 Reinforcement as Means of Revivalism This aspect of reinforcement was used commonly when the budget of the restoration process is limited as had appeared in the mission of the German Institute (which represents the German-Egyptian rescue program) as the conservation of the Darb al-Qirmiz since 1973 and completed four buildings after 12 years using simple techniques and traditional materials
Fig. 6 The collapse of the timper in house of Ali Katkuda because of the limited fund and the scarceness of after the earthquake in 1992 [6]. sophisticated restoration equipment, and materials on
Ornaments as Means of Efficient Reinforcement in Heritage Buildings 169 the local market, especially in the early years of the The shape of the roof square has been strengthened project. So the red brick, stone and timber had been by diagonal iron tie—bars anchored to the concrete mostly imported. Bonding and plastering was done beam. with mortars composed of slacked lime, sand and the New careful connections of all the joints of the addition of the crushed brrick or timber ashes as heritage wooden structure and the strengthening of the walls techniques were revived. For example, masonry with injections are an improvement of the structure that covered by salt crystals was cleaned by applying layers helped save the monument during the earth quake in of mud, new coats of plaster were reinforced with linen October 1992 [6]. fibers, and brick walls were reinforced with inserted But in the presence of the surface, water and sewage timber beams. Modern materials were only used for water can affect the concrete beams as the steel rust and restoration of decorative elements, especially painted the masonry will be affected by corrosion as had wood work, metal parts, marble mosaic, and stucco happened in El Azhar Mosque in 1960 after restoring it work [6]. but in the presence of such water problem as the used But while measuring the efficiency of all the used Portland cement contains calcium and aluminum materials, it seems that they are inefficient as they have silicates as well as calcium sulfate and some alkaline a duration time and, at the same time, they can be salts, which had penetrated into porous materials affected by the environmental conditions. causing damage, such as dark spots, efflorescence and 2.3.2 Modern Means of Reinforcement salts crystallization stresses. These means varied between using the resins (epoxy, Moreover, in all fibrous composite technologies, a acrylic, etc.), the externally or internally bonded steel proper fiber finishing or application of a coupling agent or plates or carbon laminates (carbon fiber reinforced is essential. These are surfacce coating applied to the polymers) which is parallel to the existing structures, reinforcement to protect it from damage during also the shear walls or bracings are used. processing, aid in processing and to promote adhesion One of the examples of the modern means of to matrix. They can be film forming organics and reinforcement appeared in the restoration of the dome polymers, adhesion promoters (like saline coupling of Sama Kana Building in Cairo, Egypt (Fig. 7). agents) or chemical modifiers (like silicon carbide on As after the problems of flattening the dome and the boron fibers). distortion caused by the settling of the foundation, the And these composites vary as their properties which dome was supported by wooden scaffolding internally are shown in Table 1. and a steel belt was used from outside. The wood centers were strengthened by epoxy-resins and some of them were replaced. The laths forming a covering under and over them were sewn up with strips of wire netting. A lime mortar, quite similar to the old one in its composition, with the addition of acrylic resins, was applied to the outer surfaces and a moved panel on the extrados allows people to see the restoration work carried inside the dome section. A concrete beam was fitted inside the thickness of the wall linking the wooden structure of the roof and Fig. 7 The dome of Sama Kana Building in Cairo while the dome with the vertical walls. restoring it [6].
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Table 1 Types of fibers, their properties and their uses. Types of Common use Properties Uses fibers fibers It has low electrical conductivity; It is the cheapest glass fiber; High tensile strength and modulus with individual filament strengths around 3,500 MPa and modulus around 80 GPa; Elongation-to-break is nearly 5%; E-glass accounts for 90% The ultimate use temperature of E-glass is around 500 °C; E-glass with of the glass fiber market The corrosion resistance of E-glass without boron is approximately seven times the corrosion boron or and is used mainly in a resistance of the boron-containing; without polyester matrix; Boron free E-glasses have approximately a 10% higher dielectric constant than boron It stands for “electrical”. containing E- glasses; Density: 2,620 kg/m3; Tensile strength: 3,450 MPa; Young’s modulus: 81 GPa; Strain to failure: 4.9%. These fibers are boron-free with a modified structure to enhance short and long-term acid ECR-glass was alkali resistance; manufactured specifically ECR-glass Their mechanical properties are similar to E-glass but they have less weight loss based on to resist acid and alkali sulphuric acid exposure; Glass exposure. The enhanced corrosion resistance results in an increase in cost. fiber S-glass is 10%-15% stronger than E-glass, but is otherwise similar in its properties to E-glass and R-glass. It is boron free and heat resistance is better than that of E-glass. S-glass fibers have modified silicate network giving an increase in mechanical properties. S-glass is typically selected for many structural applications because of its enhanced mechanical and S-glass, temperature performance. It should be noted that higher melt temperatures are required for R-glass and S-glass, requiring more process energy making these fibers more expensive than E-glass; Te-glass Density: 2,500 kg/m3; Tensile strength: 4,590 MPa; Young’s modulus: 89 GPa; Strain to failure: 5.7%. Applications include communication and Silica/quartz glass fibers have increasing silicon oxide with enhanced high temperature Silica/quartz satellite equipment for performance. protection against electrical discharges. They are used in circuit D-glass fibers are low volume specialist fibers with low dielectric constant which can be 40% D-glass boards because of their low lower than E-glass. dielectric constant. Carbon fiber is the reinforcement material of choice for "advanced" composites, Carbon fiber exhibits excellent fatigue resistance which does not suffer from stress rupture compared with Carbon fibers are supplied glass or aramid fibers; in tows; Untreated carbon fibers do not wet easily, so adhesion to the matrix must be achieved by Carbon reinforced mechanical interference coupled with surface treatment and chemical bonding between the Carbon fiber composites are often used fiber and the matrix of the high conductivity; for low strength Most carbon fibers are derived from polyacrylonitrile, but for even higher conductivity, fibers applications requiring derived from pitch can have three times the conductivity of copper; good electrical properties. Carbon fiber properties depend on the structure of the carbon used. Typically they come defined as standard, intermediate and high modulus fibers. Aramid fibers have the highest strength to weight ratio compared to other commercially available fibers. Kevlar manufactured by DuPont is one familiar brand name. Aramid fiber exhibits similar tensile strength to glass fibre, but can have modulus at least two times as great. Aramid fiber Aramid is very tough allowing significant energy absorption but compared to carbon, it is lower in compressive strength and has poorer adhesion to the matrix. It is also susceptible to moisture absorption. Aramid fiber properties depend on the structure used and can be tailored for high toughness or high modulus. Boron fiber actually predates carbon fiber as a high-modulus reinforcement material. The cost of boron, however, has seen its demise, with its replacement with carbon fiber. They do not Boron fiber differ greatly from glass fiber in tensile strength, but can have modulus five times that of glass. Since the objective of reinforcement is to stiffen, this is a significant advantage. Their use is confined to niche markets where the modulus advantage over carbon fiber is critical.
Ornaments as Means of Efficient Reinforcement in Heritage Buildings 171
3. Assessing the Role of the New Technology existing products rather than creating completely new in Reinforcement and Its Relation to the products. Ornaments The nano particles played a great act in the reinforcement of some constructional materials like This section of the study will demonstrate the concrete, steel and glass. Concrete becomes stronger, assessment of the new trends of reinforcement and the more durable and more easily placed, steel tougher and relation between these new trends and the ornaments. glass self-cleaning. Increased strength and durability 3.1 Role of the New Technology in Reinforcement are also part of the drive to reduce the environmental Nowadays, new technologies have appeared as footprint of the built environment by the efficient use means of reinforcement and they vary between the of resources [9]. smart materials and the nanomaterials to represent The implications of nanotechnology in building smart aspects for solving many problem, as new sector are introducing new potentialities for used properties for materials are gained by such materials. They lend building materials and surfaces technologies making them act in a form of a magic entirely new physical and mechanical properties. The solution as they do not affect the main feature of any key characteristic is not the material itself but the size object they deal with but they provide it many extra of the particles. These are responsible for properties properties. such as fire-resistance, durability and strength. 3.1.1 Smart Materials in Reinforcement The used nano-sized particles that stand out in their It may be discussed as a substitute for traditional application to construction materials are CNTs (carbon materials in many components and functions because nano tubes), nano-silica, copper nano particles and the of their features and characteristics distinguished them nano fibers of wood [10]. from the most traditional materials used in the 3.1.2.1 Carbon Nano Tubes architecture. As some smart materials show stiffness The current stars of the nano-world are another by means of the electro rheological and magneto variety of the fullerenes known as carbon nanotubes, or rheological, the potential difference could change the simply nanotubes for short, and were discovered in properties of the materials [7], as shown in Table 2. 1991 by Professor Sumio Lijima at the electronics 3.1.2 Nanoparticles and Nanomaterials in concern NEC in Tsukuba, Japan. Nanotubes consist of Reinforcement SWNTs (single-walled carbon tubes) or MWNTs Nanotechnology is the art of new sophisticated (multiwall carbon tubes) of rolled layers of graphite. technological process, which is based on using of very They have a diameter of between one and a few small particles of material either by themselves or by nanometers and can be several nanometers long. They their manipulation to create new large scale materials have a tensile strength far in excess of steel, yet are when their physical, mechanical and chemical flexible and lighter. Their thermal conductivity is also properties become more affected. It helps to improve higher than any other known material, exceeding that
Table 2 Mapping of smart materials to architectural requirements [8]. Architectural requirement Relevant material characteristic Smart material application Piezoelectric; Euler buckling; Magneto rheological; Control of structural vibration Inertial damping; Electro rheological; Strain sensing. Shape-memory alloys; Fiber optics.
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of diamond. Their key properties—great strength coupled with low weight—are predestined for use in future composite materials. Nanotubes can act as semiconductors or as conductors. Their electric conductivity is excellent, and as such nanowires are of great interest for electronic applications such as minute circuits and a generally more efficient use of electricity. Fig. 8 The Shimizu TRY 2004 mega-city pyramid. The mechanical properties described are, however, only attained when the atomic structure of the nanotubes is faultless. Any defects result in impaired performance. A particularly ingenious variant developed for certain applications is filled with nanotubes which are great strength coupled with low weight. As they are up to 50 times stronger yet 10 times lighter than steel [9]. One of the examples for such material is the Shimizu TRY 2004 mega-city pyramid (Fig. 8) which would house 750,000 people of height 2,004 m high so the proposed material used in the structure is nano carbon as it represents a super-strong light weight material. Another example is the carbon tower Peter Testa (Fig. 9) as this project is a 40-story skyscraper which is proposed to be the lightest and strongest building so it will be made of composites mostly carbon fibers, glass Fig. 9 Carbon tower Peter Testa. fibers as they are strong and light weight and easily molded into an almost endless variety of shape, and the Nanoparticles are used to penetrate and close small carbon fibers will form 40 strands about 1 inch wide cracks on the concrete surface and, in strengthening and 650 feet long that are arrayed in a helicoidally applications, the matrices form a strong bond between pattern. the surface of the concrete and the fiber reinforcement. Moreover, carbon nanotubes show that, not only do The ability of the samples to sustain load after cracking these materials significantly increase the compressive is greatly improved by the carbon tows and both the strength of cement mortar specimens, they also change matrix and the interface are durable under wetting, their electrical properties which can be used for health drying and scaling (scraping) conditions. monitoring and damage detection. SCC But nanotubes are always mixed with other materials (self-compacting concrete) is one that does not need or applied to surfaces. Additional work is needed in vibration in order to level off and achieve consolidation. order to establish the optimum values of carbon This represents a significant advance in the reduction nanotubes and dispersing agents in the mix design of the energy needed to build concrete structures and parameters [9]. can offer benefits of up to 50% in labor costs, due to a 3.1.2.2 Nano-Silica sustainability issue that is being poured up to 80% Nano-silica’s addition to cement based materials can faster and having reduced wear and tear on formwork. lead to improvements in durability and the compressive
Ornaments as Means of Efficient Reinforcement in Heritage Buildings 173 strength of the refined material (1 to 6 times higher at of silica and alumina nanoparticles and hydrophobic different ages). For over 80 years, the micro silica has polymers. And secondly, mechanical studies of bones been used widely to be added to concrete to give it high have been adapted to model wood, for instance, in the compressive strength and water and chemical drying process as shown in Fig. 12 [10]. resistance. 3.2 Relation between the Ornaments in the Heritage At the same time, the “ethyl-ortho-silicate” resin Buildings and the Role of Reinforcement plays an important role in surface consolidation of stone as it is available in 75 % up to 100 % (solvent free) Nowadays, most of the global high rise buildings concentration. One of the most determinative refer to the exoskeleton to glorify the natural lighting characteristics is given by the penetration depth of the and the sense of the free slabs. As this skeleton presents liquid into the stone surface (and of course the porosity means of ornaments, at the same time, it refers to the of the stone material) to obtain better and deeper reinforcement of the buildings as shown in the O-14 penetration, one suggests “spray-flow” technique (i.e., Tower in Dubai, by Reiser + Umemoto, who uses a repeated flow down of the liquid up to full saturation of concrete shell to provide an efficient structural the stone surface). exoskeleton (Fig. 13) [11]. 3.1.2.3 Copper Nanoparticles Referring to the heritage buildings, the ornaments Copper nanoparticles reduce the surface unevenness sometimes represent means of structural elements as of steel which then limits the number of stress risers shown in the muqarnas vault, Bishiriya Madrasa in and hence fatigue cracking (Figs. 10 and 11). Baghdad in 1255, as the muqarnas elements are formed 3.1.2.4 Nanotechnology and Wood of terracotta panels decorated with Arabesques which Wood is composed of nanotubes or “nano fibers”, represents the Abbasid architecture (Fig. 14) [12]. namely, lignocellulosic (woody tissue) elements which are twice as strong as steel. Harvesting these nano fibers would lead to a new paradigm in sustainable construction as both the production and use would be part of a renewable cycle. Some developers have speculated that building functionality onto lignocellulosic surfaces at the nanoscale could open new opportunities for such things as selfsterilizing surfaces, internal self-repair and electronic Fig. 10 Seri Wawasan Bridge, Putrajaya (Malaysia’s lignocellulosic devices. These nonobtrusive active or administrative centre). passive nanoscale sensors would provide feedback on product performance and environmental conditions during service by monitoring structural loads, heat losses or gains, temperatures, moisture content, decay fungi and loss of conditioned air. Due to its natural origins, wood is leading the way in cross-disciplinary research and modeling techniques which have already borne fruit in at least two areas. Firstly, BASF has developed a highly water repellent coating based on the Fig. 11 Jubilee Church, Rome, Italy, Richard Meier, 2003, actions of the lotus leaf as a result of the incorporation (TX MilIenium, TX Active, photocatalytic cement) [9].
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Fig. 12 Wood-plastic composites carbon nanofibers and nanoclayes improve stiffness and are less-toxic alternative to traditional treated timber [12].
Fig. 13 The O-14 Tower in Dubai, by Reiser and Umemoto [11]. To the left, the exoskeleton seems to be under construction, while to the right, it seems to be completed.
Another example is shown in the dome of the Great Mosque of Tlemcen, as the ribbed dome represents a collection of multiple arches and the space between them is filled by peneferated ornaments [12] as shown in Fig. 15. Sometimes there are special ornaments that take place in the building in different positions as that could play a role in supporting the structural elements as an Fig. 14 Muqarnas vault, Bishiriya Madrasa in Baghdad in 1255 [12] . outer shells or belts for support, the walls, the columns, the roofs, the ceilings, as most of the heritage buildings especially in the Arabian town refer to the decorative art which use the stucco decoration that is related to the Samarra style in which the field is divided by decorated band containing recognizable leaves growing from veins, where the stucco is a material made of gypsum, lime, sand and water used while still wet for architectural decoration, stucco dries very quickly in the sun but is not waterproof. It could either be applied
Fig. 15 Dome of the Great Mosque of Tlemcen [12]. straight onto the building or used in prefabricated
Ornaments as Means of Efficient Reinforcement in Heritage Buildings 175 panels, which were then fixed to the building [12]. Such stucco appeared on the columns of the palaces, the castles, the mosques as shown in Mosque of Nayin, mid-10th century, in the central Iranian town. It is a good example of a provincial Abbasid mosque, the decorated patterns used are called stucco in a variant of the Samarra styles and this shows how the metropolitan style was adapted in provinces (Fig. 16) [12]. Some stucco ornaments appeared on the minarets and the domes as shown in the high Mamluk minaret in Mausoleum of Qaitbai (Fig. 17), 1472-1474, and the impressive domes of Sultan Barsbai are complex in the eastern cemetery of Cairo (Fig. 18), 1432. The stucco ornaments appeared also on the walls of the buildings especially on the arches of the doors as they appeared to be penetrated as shown in the facade of the Almohad Palace in Seville in the 2nd half of the Fig. 17 Mausoleum of Qaitbai, 1472-1474 [12]. 12th century called “The Yeso Patio”, as the pattern used in the portico entrance and its envelope seem to be reached in decorations, the pointed arches whose archivolt is made up of little branches with leaves, which show the plaster or stucco courtyard (Fig. 19). Also, the walls of ornaments came semi penetrated or bulky as shown consecutively in the southern palace wing of Aljaferia of Zaragoza, 2nd half of the 11th century outside as the portico whose arcade comprises
Fig. 18 The complex of Sultan Barsbai in the eastern cemetery of Cairo, 1432 [12].
interlaced semicircular arches with unique ornamented faces. As the ornamentation is constructed from a repeated framing of the basic elements forming the arches, and is a typical taifa period innovation (Fig. 20). And the façade of the most beautiful Mudejar palaces in Spain is shown in Fig. 21.
Fig. 16 Mosque of Nayin, mid-10th century, in the central Ornament patterns have appeared on the arches as Iranian town [12]. shown in the archivolt over the first gateway of the
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Aleppo citadel which is decorated with figurative relief as the motif traditionally used in the art of the Anatolian Seljuks and Artuqids who decorated many citadels, city walls and caravanserais with similar figurative images (Fig. 22). Also, ornaments appeared on the walls of the Mihrab as shown in the Great Mosque of Koairouan, as it is adorned with perforated wall panel (Fig. 23).
Fig. 22 The archivolt over the first gateway of the Aleppo 4. Results and Discussions [12].
Selection of materials for use in architecture is always based on various criteria as performance and cost have obvious role in this selection, but final
Fig. 19 The façade of the Almohad Palace in Seville in the 2nd half of the 12th century [12].
Fig. 23 Mihrab of Great Mosque of Koairouan [12].
selection is often done based on appearance, beauty Fig. 20 Southern palace wing of Aljaferia of Zaragoza in the 2nd half of the 11th century [12]. and aesthetic, ease of construction with regard to human resource skills, availability of local or regional, as well as materials used in the building which are in the near place. In the meanwhile, efficiency means both low weight and low cost because any fibers which do not carry much load could probably be removed. But many progressive materials have emerged for preparing the fastest visual appearance and thus providing appropriate tools for interior and exterior of Fig. 21 Alcazar, Seville 1530-1369, is one of the most beautiful Mudejar palaces in Spain [12]. buildings. Thus, modern architects often think about
Ornaments as Means of Efficient Reinforcement in Heritage Buildings 177 materials as a part of the composition of design moreover by the role the ornaments play in through which materials can be selected and reinforcement in the latest era, we can prove that accepted as level of structure or combination and visual. ornaments can play a great role in the reinforcement It is in such an atmosphere and environment that many process in the heritage buildings especially while people reached to the approaches of using smart promoting their presence in several positions can be materials. responsible for reinforcement. Nanotechnology introduces promising economical 5. Conclusions solutions and products to achieve reliable sustainable environment. And the development of nanotubes is Before planning alterations or other changes to continually being optimized as high-quality nanotubes heritage items, it is necessary to first understand the can now be produced much more cheaply and in large reasons for its heritage status. Why is it significant? quantities. Although nanotubes can now be produced What is its historical context and history of its comparatively economically, they are still too development? Is it a fine example of an important class expensive for use in large quantities. of items? Does the community value the place? Does it Concerning the corrosion problems in concrete inform us about our cultural identity? As these factors products, nanotechnology can offer smart determine how an item can be changed without solutions providing coatings that respond to external negatively affecting its heritage value and what type of agents with a “response” that can repair or prevent heritage management is appropriate. damage. Thus, even with the limited funds available, a Moreover, nanoparticles are reducing the effects of strategy must be agreed upon that will insure hydrogen embrittlement and improving the steel protection of all the indexed monuments. But for micro-structure through reducing the effects of the undertaking complete conservation, some priorities inter-granular cementite phase. The addition of must be set that would systematically direct effort and nanoparticles of magnesium and calcium makes the recourses. HAZ (heat affected zone) grains finer in plate steel and Properties of the new materials need to be this leads to an increase in weld toughness. Two compatible with that of the historic materials so that the relatively new products that are available today are new materials do not damage the historic ones. Sandvik Nanoflex (produced by Sandvik Materials Compatibility of historic character, on the other hand, Technology) and MMFX2 steel (produced by MMFX is more subjective and based upon similarity of visual Steel Corp). Both are corrosion resistant, but have characteristics such as color, size, texture, scale, mass, different mechanical properties and are the result of proportion, configuration, rhythm, ratio of solids to different applications of nanotechnology. Sandvik voids, ornamentation, details, etc.. If few or none of the Nanoflex has both the desirable qualities of high characteristics of the new material harmonize with the strength and resistance to corrosion. MMFX2 steel has historic materials, the effect may be very jarring and a modified nano-structure that makes it corrosion detract from the artistic and architectural expression of resistant and it is an alternative to conventional the historic resource. If all of the visual characteristics stainless steel, but at a lower cost. Moreover, the are matched, it becomes very difficult to distinguish nanomaterials while added to concrete reduced need what is historic and what is new. for maintenance (easy to clean, longer cleaning Replacement of missing parts of the design must be intervals) and/or operational upkeep. based on physical or photographic documentation, not So by the effort gained by scientists in materials, conjecture.
178 Ornaments as Means of Efficient Reinforcement in Heritage Buildings
References Cultural Heritage. Egypt: The American University in Cairo Press. [1] Bowron, G., and Harris, J. 1994. “Guidelines for [6] Jere, L. B. 1995. The Restoration and Conservation of Preparing Conservation Plans, New Zealand Historic Islamic Monuments in Egypt. Egypt: The American Places Trust.” In The Conservation Plan: A Guide to the University in Cairo Press. Preparation of Conservation Plans for Places of [7] Addington, M., and Schodek, D. 2005. Smart Materials European Cultural Significance, edited by Kerr, J. S. and New Technologies for the Architecture and Design Sydney: National Trust of Australia. Professions. Britain: Architectural Press. [2] NSW (New South Wales) Heritage Office. 1996. [8] Schwartz, M. M. 2002. Smart Material—Encyclopedia. “Heritage Information Series: A Guide to the Heritage New York: A Wiley-Interscience Publication. System.” Accessed January 1, 2013. [9] Leydecker, S. 2008. Nano Materials in Architecture, http://www.heritage.nsw.gov.au. Interior Architecture and Design. London: [3] Sydney Water. 2009. Veteran Hall Conservation BirkhauserVerlag AG. Management Plan, Archaeological Site, Prospect. [10] Mann, S. 2006. Nanotechnology and Construction. Unpublished report based on a study conducted by Nanoforum report. Archaeology and Heritage Pty Ltd. [11] Dunn, N. 2012. Digital Fabrication in Architecture. [4] Heritage Council of New Wales. 2009. Assessing London: Laurence King Publishing. Significance for Historical Archaeological Sites and [12] Hattstein, M., and Delius, P. 2007. Islam Art and Relics. Australia: Heritage Council of New Wales. Architecture, edited by Ullmann, H. F. Accessed January [5] De Naeyer, André. 2000. New Materials for Safeguarding 1, 2013. http://www.ullmann-publishing.com.
Journal of Civil Engineering and Architecture 9 (2015) 179-187 doi: 10.17265/1934-7359/2015.02.006 D DAVID PUBLISHING
Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil
Marcos Antonio Leite Frandoloso and Luciana Londero Brandli Faculty of Engineering and Architecture, University of Passo Fundo, Passo Fundo 99052-900, Brazil
Abstract: The paper deals with the energy and indoor comfort on buildings of UPF (University of Passo Fundo), located in southern Brazil, in order to improve the eco-efficiency concepts in the university’s building stock, reinforcing its responsibility towards sustainable development. The factors that affect thermal performance and the energy consumption of two case studies were identified, including the general characteristics of the envelope and the indoor conditions. The simulations with DesignBuilder software compare the energy and thermal performance of both cases: those results allow the identification of their positive and negative aspects, as well as making a co-relation with the students’ sensations of comfort—obtained through PMV (predicted mean vote). The research indicates that it will be possible to improve eco-efficiency of existing and new buildings and campuses by retrofitting and upgrading it with regard to better indoor conditions that really correspond to climate conditions (hot and humid summers, and cold and damp winters), using passive strategies for heating and cooling and at the same time to improve rational use of natural resources and to reduce the environmental impact. Probably, giving comfortable conditions to the users will increase energy consumption, but there is a potential reduction of lighting and equipment that could minimize this impact.
Key words: Comfort energy efficiency, eco-efficiency, indoor comfort, university buildings, building retrofitting.
1. Introduction Business Council on Sustainable Development), which defines seven elaborated elements to achieve The main role of universities is remarkable as well eco-efficiency applied to goods and services: reducing as their responsibility in preparing students for a more the material requirements, reducing energy intensity, conscious and responsible professional future through reducing toxic dispersion, enhancing materials knowledge and practical experience. They also have recyclability, maximizing sustainable use of to be an example of concrete actions in order to renewable resources, extending product durability and achieve the principles of a sustainable society in a increasing the service intensity. collaborative and responsible way by involving the On the other hand, many authors have been entire university community in the imperative process discussing within interdisciplinary teams and also of changing procedures and habits. exchanging their experiences in order to accelerate the Various factors contribute to the process of rate at educational institutions to foster and underpin evaluation of the level of adherence to concepts of the values, knowledge and actions to help their sustainability within these areas. Kibert [1] refers to students transform society from unsustainable to eco-efficiency, which includes the analysis of sustainable patterns [2]. environmental impact and costs as factors of Frandoloso et al. [3] present that being efficient administration efficiency evaluation of institutions or means reaching the proposed objectives. In this way, companies. The author quotes the WBCSD (World the attainment of energy efficiency takes place when the objectives are obtained by equally employing the Corresponding author: Marcos Antonio Leite Frandoloso, Ph.D. candidate, research fields: renewable energy, least amount of resources possible. In other words, a eco-efficiency, university buildings, energy simulation and building which is efficient in terms of energy should thermal performance. E-mail: [email protected].
180 Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil carry out all its activities with the lowest possible According to Ferreira et al. [6], the implementation consumption of electricity and in a broader manner, of EMS is a holistic and integrated way to tackle all the raw materials it uses on all phases of its environmental impacts that can be extremely valuable lifespan: resources on planning embodied energy of to improve eco-efficiency of university and promote materials and construction systems, use and operation sustainable learning. and refurbishment. The study also links the 2. Method eco-efficiency of the user’s requirements to reach an ideal indoor comfort. In order to analyse the thermal and energy output of Braungart and McDonough [4] consider the the university buildings, energy auditing methodology eco-efficient building by one that “is a big energy was adopted, the same that was used in the park saver”. But even, it should achieve a more complex constructed by the UPC (Polytechnic University of design, being a “building that celebrates a range of Catalonia) [7-9], which made it possible to identify cultural and natural pleasure—sun, light, air, nature, each building in relation to the different sources of even food—in order to enhance the lives of the people energy and their respective uses. who work there”. The energy audit adopted in this research identifies The higher education institutions can be compared and evaluates the buildings and system characteristics to small cities, according to Frandoloso et al. [5], regarding the energy sources. The study’s premise is exhibiting in many cases complex infra-structures for that the energy consumption is related to three main their operation, which demand natural resources and factors: the energy demand (building location and generate environmental impact. In the case of UPF building shell); the performance and efficiency of (University of Passo Fundo), for example, in August systems and installations; and the management of use 2009, the energy consumption was more than 314,000 and occupation (intensity and area-time distribution). kWh, corresponding to approximately 3,000 The analysis is based on two sources of information: residencies with four inhabitants or, similarly, to a the “static” data are related to the building location town of 12,000 inhabitants. (outdoor and indoor conditions), building The main goal of this work is to evaluate the energy characteristics (architecture and construction), systems and thermal performance of the building stock of the and infrastructure and energy resources. On the other University of Passo Fundo, Rio Grande do Sul, and hand, the “dynamic” data were obtained by modelling their interrelation with indoor users’ comfort. Then, the occupied area, the number of users and the kind of the aim is to propose guidelines to include or to activities together with their energy performance increase eco-efficiency in the planning of university through an automatic control of energy consumption. buildings and campuses. For the application of this methodology at the These guidelines can then be incorporated within an University of Passo Fundo, a characterization study [3] institutional plan of environmental management to was initially developed in Campus 1, the main UPF include sustainable development within the areas of campus with 341 ha, where the current use of energy administration and teaching, embracing these was identified. In accordance with the building stock, principles in all daily activities (graduation, research, two buildings were selected: the FEAR (Faculty of extension and administration), following the Engineering and Architecture). These buildings are principles of an EMS (Environmental Management representative of the diverse construction typologies System) of ISO 14.001 and EnMS (Energy in Campus 1: the G1 building, administrative and Management System) of ISO 50001. teaching block of Faculty of Engineering and
Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at 181 University of Passo Fundo, Brazil
Architecture—Fig. 1, and the L1 building with Then, a questionnaire was applied to students of laboratories and classrooms and the FEAR and CEPA four classrooms, located in both buildings, in different (Centre of Research in Agriculture)—Fig. 2. Two periods of day and year, in order to identify their rooms from each building were selected, located at the opinion about comfort classified in the ASHRAE’s opposite orientation. (American Society of Heating, Refrigerating and The real conditions of the buildings were noted Air-Conditioning Engineers) Bedford scale [13]. concurrently through record cards and temperature 3. UPF and the Energy Resources and humidity measuring devices (Data-loggers Testo, models 175-H2 e 175-T1), analogical energy gauges The UPF is a multi-campus university, located in and software (SmartGateM—Gestal). The southern Brazil. The main campus occupies a comparative analyses of the thermal advantages were peripheral zone of the city, the building park is around obtained by applying the software DesignBuilder [10]. 110,000 m2, receiving a population of around 22,000 The evaluation of the standards of students’ users (including students, teachers and staff) with comfort had adopted the Fanger’s PMV (predicted several impacts on the neighborhood context and mean vote) [11] and Fanger and Toftun [12], using mobility. averages of the internal and external environment The climatic conditions in Passo Fundo indicate a variables (average radiant temperature, temperature, warm summer and cold winter, with a subtropical humidity and relative air speed) and the global climate (Csa) by the Köppen classification [14]. These temperature. characteristics indicate the need for improvement of passive solar strategies for cooling and heating, as can be applied using Givoni’s psychometric chart shown in Fig. 3. In previous studies [3, 5], it was noted that within the environmental activities of UPF, besides another actions, energy consumption management of the campuses was considered, such as the installation of a group generator. When the comparison between energy consumption and constructed area was observed (Table 1), the correspondence increased from 43 kWh/m2 (2004) to Fig. 1 G1 building—north facade. 2 51.42 kWh/m (2010). In 2009, the energy consumption increased 24.15%, due to the expansion of computerization in all administrative and academic areas and, of particular significance, the increase of the use of air conditioning in the laboratories. This increase in energy consumption was correspondent to the increase in costs of approximately 60%, which was seen to occur for the period of differentiation of subsidies from the energy supplier. The energy consumption on Campus I corresponds to around 85% of the total consumption of UPF,
Fig. 2 L1 building—north facade. indicating the relevance of a study of tools for control
182 Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil
Fig. 3 Givoni’s psychrometric chart to Passo Fundo by Climate Consultant [15].
Table 1 Evolution of construction area, energy which made it possible to control and monitor online, consumption and costs (2004-2010). permitting the detection of specific problems. Energy Costs Constructed Year consumption (thousand Monitoring can take place when the pre-established area (m2) (GWh) R$) limits are exceeded and it is also possible to 2004 88,987.99 3.91 1,557.56 disconnect these installations or activate the 2005 90,735.15 3.98 1,912.87 2005/2004 (%) 1.96 1.70 22.81 equipment using the independent generator. 2006 99,071.34 3.69 1,314.78 2006/2005 (%) 9.19 -7.20 -31.27 4. Energy Performance 2007 99,147.84 4.42 1,439.72 The first stage of the research was the collection of 2007/2006 (%) 0.08 19.68 9.50 2008 103,293.84 4.42 1,384.08 static data, in order to know about the general 2008/2007 (%) 4.18 0.02 -3.86 characteristics of the buildings and their internal 2009 108,104.47 5.49 2,214.30 spaces, presenting their construction and architectonic 2009/2008 (%) 4.66 24.15 59.98 characteristics [3]. 2010 109,675.24 5.63 2,231.39 The other step of the evaluation was to compile 2010/2009 (%) 1.45 2.71 -3.74 dynamic data obtained by the energy consumption and energy management which, as a consequence, monitoring for different uses and subsequent area use would bring financial control. and occupations. According to this, equipment reaches It should also be mentioned that, until June 2009, more than 65% of energy use at L1, due to the high energy consumption control was centralised, there power degree in engineering laboratories and in the being no division into units or isolated buildings. CEPA, specifically concerning the quality control of From this moment, a decentralization programme was foodstuffs such as milk and other products of animal set up (SmartGateM—Gestal), with the installation of origin. These commodities, aside from demanding equipment in each of the energy consumption units, high power equipment, require internal temperature
Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at 183 University of Passo Fundo, Brazil control of the atmosphere in building L1. On the other theoretical number of users of 799 (G1) and 645 (L1), hand, a small percentage in relation to lighting is based on maximum capacity of classrooms by class related to the fact that the building is of more recent groups and practical laboratories (information construction, using more efficient lighting devices technology and classes) and the real occupation of the (32 W). specialized laboratories in building L1. Regarding the G1 building, the Information The occupation diagnosis of the L1 building shows Technology Laboratory of FEAR implies that there is that the greatest rate of occupation is focused in the around 56% of power because of the equipments. evening period because of the types of courses that Also, the building is of an older construction, still use the classrooms and this exact same pattern of using high energy consuming lamps with low occupation is observed in the following semesters. In efficiency output (110 W), which results in a total of the daytime period, especially in the morning, the 11.41%. main use is by the CEPA laboratories, which represent In both buildings, the areas with air conditioning external services from the university are basically restricted to some laboratories which (SARLE—laboratory that analyses the quality of milk, require temperature control, which corresponds to for example), with equipment that is in permanent 29.17% in L1 and only 12.72% in G1. This results in function. energy consumption below the thermal demand which Fig. 4 shows the monthly energy consumption at is really necessary to find the ideal conditions of G1 and L1 buildings, where the occupation patters comfort, when compared with the analysis of the represent a relevant impact. thermal output. 5. Thermal Performance For the dynamic data, it means the variables in accordance with time, the uses and occupation of each G1 was built using the original construction system space of both buildings were identified, showing a (single masonry walls and expanded polystyrene
30,000
25,000
20,000
15,000
10,000
5,000 Energy consumption(kWh) 0 January February March April May June July August September October November December
Fig. 4 Comparative energy consumption (2009-2010) of G1 and L1 buildings.
184 Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil
ceiling in the upper floor). The L1 was built in the For the cold periods, the measurements make the most recent typology with double brick walls and environmental engineering department (G1) the concrete ceiling [3]. In spite of almost the same minimum indoor temperature which reaches 9.7 ºC construction characteristics, using the software (outdoor temperature). It means below 18 ºC by DesignBuilder was calculated using the envelope Givoni’s [17] suggestion for winter (from 18 ºC to 27 properties with a U = 1.255 W/m2·K in G1 and U = ºC). 1.105 W/m2·K in L1. Both thermal properties for The preliminary simulation of energy and thermal walls when compared with the precepts of NBR performance by DesignBuilder confirms that the 15575 [16] are below 2.50 W/m2·K, the minimal intense thermal gains are closely related with the thermal transmittance of the external walls indicated constructive and occupational architectonic typology to the Bioclimatic Zone Z2, in accordance with the and the conditions of solar protection. Brazilian Classification for Buildings and According to the DesignBuilder simulations, Construction Normative. although in building G1, 67.61% is relative to the On the other hand, typological architectonic gains of the equipment (32.68% by the computers), characteristics, solar orientation and protection are 24.9% by solar radiation and 7.36% by occupation. In distinct, as can be seen in Figs. 1 and 2, especially due building L1, 34.19% of thermal gains are by solar to the fact that, in building G1, solar protectors are radiation, with other factors presenting similar results present in the openings on the north and south sides. between them, despite a greater potency of equipment Besides, L1 does not possess protection systems except for the application of blinds and/or internal shutters in some of the windows or, in cases of emergency, paper fixed onto the windows to control the entrance of solar radiation and dazzling from the sun, as shown in Fig. 5. The indoor conditions were collected in two rooms from each building: meat laboratory (L1) and the architecture department office (G1) which are orientated towards the north, and the practice laboratory (L1) and the environmental engineering Fig. 5 “Alternative” solution for controlling solar department (G1) towards the south, with none of them radiation—north facade of L1. possessing artificial conditioning. Table 2 Indoor conditions measurement. In accordance with the indoor temperature Indoor Room Min. Day Max. Day conditions measurements and relative humidity (Table 2), the December RH (%) 20.0 87.1 March 22 maximum internal temperature recorded during the set G1 architecture 9 department (N) Temperature 10.8 July 21 36.7 February 5 period (2010) was 40.3 ºC at meat laboratory (L1) (°C) G1 which occurred at December 26, while the maximum environmental Temperature 9.7 July 16 33.9 February 7 external temperature reached 29.2 ºC with a minimum engineering (°C) department (S) of 15 ºC. This temperature is above the upper limit RH (%) 20.2 July 13 84.7 July 19 L1 meat Temperature recommended for acceptable condition in still air for laboratory (N) 13.4 July 20 39.0 April 3 (°C) people living in developing countries by Givoni [17] L1 practice Temperature December 10.5 August 4 40.3 from 20 ºC to 29 ºC in summer. laboratory (S) (°C) 26
Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at 185 University of Passo Fundo, Brazil
(61.86%). The comparison between the thermal benefits is presented in Fig. 6.
6. Indoor Comfort Performance
The prediction model of thermal comfort for building users as well as the evaluation of thermal acceptance of internal environments is a subject normalized through ISO 7730 pattern [18]. The PMV or analytic sensation of thermal comfort was obtained from the model through the thermal balance between Fig. 6 Internal thermal gains of L1 and G1 [3]. man and the environment, where the generation of heat by the organism due to the performance of an activity must be dissipated in the same rate to the environment, through the mechanisms of thermal exchanges, meaning convection, radiation, evaporation and conduction. In order to evaluate the users, perception about their education environment, some questionnaires were applied, demanding their feelings with the temperature and humidity variables. Also, they were questioned Fig. 7 PMV/PPD of male students at practice about their clothes, which identify the proprieties and, laboratory—L1, afternoon March 31, 2010. finally, to calculate [19] the PPD (predicted percentage of people dissatisfied with their thermal environment). For instance, with the application of questionnaires for users in sedentary occupation at the practice laboratory—L1, adopting Fanger’s PMV methodology [11] and the Bedford scale [13], Fig. 7 shows that, in relation to the indoor, the condition is 100%: 54.55% presented a sensation of little heat (+1), 27.27% with heat (+2) and 9.09% with a lot of heat (+3). The temperature registers obtained in the Fig. 8 PMV/PPD of female students at practice laboratory—L1, afternoon March 31, 2010. classroom occupied by the students were from a minimum of 26.6 ºC to a maximum of 28.8 ºC. percentage of male and female students have the same Fig. 8 demonstrates the dissatisfaction of the female sensation to hot times, it means a little or a lot of heat students in relation to the environmental conditions: (+1 to +3). 16.67% described a comfortable thermal sensation, It was observed that, even in cold conditions, the neither feeling hot nor cold (0), 50% presented low users seem to present a kind of accommodation to heat sensation (+1) and 27.78% hot (+2). extremely uncomfortable situations, not only in winter The study has also been applied to rooms at G1 but also in summer, under or above the mentioned building in different days, showing that the major Givoni’s limits.
186 Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at University of Passo Fundo, Brazil 7. Conclusions and Guidelines for Improving utilizing adequate thermal insulation coverings and Eco-efficiency at UPF the application of sustainable construction principles: for the existing buildings, a refurbishing and First of all, the main role of universities is retrofitting program might be feasible. remarkable, as well as their responsibility in preparing The architectural design should also be revised, students for a more conscious and responsible pointed solar orientation (especially to laboratories professional future through knowledge and practical where the indoor conditions are more restricted), experience, and also to be an example of concrete opening design that can guarantee effective reduction actions in order to achieve the principles of a of solar effect besides passive heating and cooling sustainable society in a collaborative and responsible strategies. way, by involving the entire university community in In order to improve projects for upgrading with the the imperative process of changing procedures and implementation of better thermal comfort conditions habits. The research indicates that it will be possible to that corresponds to the local complex climatic provide some criteria in order to improve the building conditions (hot and humid in the summer and cold and stock quality by upgrading it with regard to better damp in the winter), it is also very important to indoor conditions that really correspond to climate increase use of efficient natural resources and a conditions (hot and humid summers and cold and reduction in the associated environmental impact. damp winters), using passive strategies for heating The results should be analysed, taking into and cooling and, at the same time, to improve the consideration all the factors that present an influence efficient and rational use of natural resources, and to on the thermal and energy output, especially reduce the environmental impact. Probably, the concerning the use and occupation of the spaces and improvement of comfortable conditions will increase the efficiency of the equipment in areas such as energy consumption, but there is a potential reduction illumination and air conditioning, or the various of lighting and use of equipment that could minimize equipments that are part of the scope of the this impact. developing research. In this way, the systematic It was observed that in relation to the thermal analysis indicates that, as a priority, to meet the real performance of the studied buildings, the energy needs of the users, energy consumption should be demand has a direct influence on the architectonic greater because living/working conditions in both typology and the openings design. The lower buildings are inexistent, especially during the cold performance of buildings is also due to the periods. unfavourable orientation, in particular, of the The energy audit method applied to universities laboratories, together with a lack of ventilation. All constitutes a valuable tool to understand the real these factors contribute to a high thermal charge for condition of each building in order to propose a air conditioning reflecting directly by a consequential concrete plan of action and investments to achieve increase in energy consumption. energy efficiency, with corresponding economic After this study, it was possible to suggest some results for the entire building stock. This means guidelines to increase eco-efficiency in the building achieving eco-efficiency in all its dimensions: stock at UPF, both in existent buildings and those yet economic, social and environmental. to be constructed. Finally, it will be possible to improve the In a general way, a revision of construction methodology as an operational tool to help in decision parameters for new constructions would be necessary, making during the whole life cycle, focusing the
Assessment and Guidelines to Improve Eco-efficiency and Indoor Comfort at 187 University of Passo Fundo, Brazil process of design, construction and use of buildings. [7] Plazas, F. L. 2006. Sobre el Uso y la Gestión Como los Factores Principales que Determinan el Consumo de In the specific case of the application to the Energía en la Edificación (On the Use and Management University of Passo Fundo, the final results of the as the Main Factors That Determine Energy research might provide elements to propose an Consumption in Buildings). Barcelona: UPC (Polytechnic instrument to improve the eco-efficiency performance University of Catalonia). (in Spanish) [8] Gonzáles, M. B., Rodríguez, I., and Ruiz, G. 2006. of the buildings stock in the campus and also to Avaluació Energètica d’Edificis: Experiència de la UPC elaborate the guidelines for “Environmental (Building Energy Evaluation: Experience of UPC, an Efficiency and Energy Programme” applicable to all Analysis Methodology). Barcelona: UPC. (in Catalan) the campuses. In this way, the use of DesignBuider [9] Burgos, A. C. 2009. La Qualitat Ambiental als Edificis (The Environmental Quality of Buildings). Barcelona: simulations of real models and the refurbishment Government of Catalonia. (in Catalan) proposals show a feasible tool to compare results of [10] DesignBuilder. 2011. “DesignBuilder EnergyPlus performance, which should be evaluated by an Simulation Documentation. DesignBuilder v3.1.” economic approach, that can be helpful during the Accessed December 16, 2012. http://www.designbuilder.co.uk. taking decision process. [11] Fanger, P. O. 1970. Thermal Comfort: Analysis and References Application in Environmental Engineering. Copenhagen: Danish Technical Press. [1] Kibert, C. J. 2005. Sustainable Construction: Green [12] Fanger, P. O., and Toftum, J. 2002. “Extension of the Building Design and Delivery. USA: John Wiley & Sons. PMV Model to Non-air-Conditions Buildings in Warm [2] García, F. J. L., Kevany, K., and Huising, D. 2006. Climates.” Energy and Buildings 34 (6): 533-6. “Sustainability in Higher Education: What’s [13] ASHRAE. 2004. ASHRAE Standard 55: Thermal Happening?.” Journal of Cleaner Production 14 (9-11): Environmental Conditions for Human Occupancy. USA: 757-60. ASHRAE. [3] Frandoloso, M. A. L., Brandli, L. L., Couto, F. A., and [14] Trewartha, G. 1980. An Introduction to Climate. 5 ed.. Wildner, P. D. 2010. “The Energy and Thermal New York: McGraw-Hill. Performance of Two University Buildings in Southern [15] Ligget, R., and Milne, M. 2012. “Climate Consultant 5.4 Brazil with the Aim of Achieving Environmental (Build 4).” Software, UCLA Energy Design Tool Group. Efficiency.” In ERSCP-EMSU (The Energy and Thermal Accessed February 7, 2013. Performance of Two University Buildings in Southern http://www.energy-design-tools. aud.ucla.edu. Brazil with the Aim of Achieving Environmental [16] ABNT (Brazilian Association of Technical Standards). Efficiency) 2010 Proceedings. Accessed April 21, 2012. 2008. NBR 15575: Edifícios Habitacionais de Até Cinco http://repository.tudelft.nl/view/conferencepapers/uuid%3 Pavimentos (Residential Buildings of Up to Five Floors). Abcdd6e05-89d6-45e5-ab51-890e564d83f7/. Brazil: ABNT. (in Portuguese) [4] Braungart, M., and McDonough, W. 2009. Cradle to [17] Givoni, B. 1992. “Comfort, Climate Analysis and Cradle: Re-making the Way We Make Things. London: Building Design Guidelines.” Energy and Buildings 18: Vintage Books. 11-23. [5] Frandoloso, M. A. L., Brandli, L. L., and Dias, F. P. 2012. [18] ISO. 2005. ISO 7730: Ergonomics of the Thermal “Energy and Thermal Performance in Relation to the Environment—Analytical Determination and Comfort of Users of University Buildings in Southern Interpretation of Thermal Comfort Using Calculation of Brazil”. In IADIS International Conference on the PMV and PPD Indices and Local Thermal Comfort Sustainability, Technology and Education—STE2012 Criteria. Geneva: ISO. Proceedings, 37-44. [19] LabEEE-UFSC (Energy Efficiency in Buildings [6] Ferreira, A. J. D., Lopes, M. A. R., and Morais, J. P. F. Laboratory, Federal University of Santa Catarina). 2008. 2006. “Environmental Management and Audit Schemes “Analysis CST, Software. v. 2.1.” LabEEE—UFSC. Implementation as an Educational Tool for Accessed August 13, 2010. Sustainability.” Journal of Cleaner Production 14 (9-11): http://www.labeee.ufsc.br/downloads/softwares. (in 973-82. Portuguese)
Journal of Civil Engineering and Architecture 9 (2015) 188-192 doi: 10.17265/1934-7359/2015.02.007 D DAVID PUBLISHING
A Review: Investigation of Bioplastics
Ezgi Bezirhan Arikan and Havva Duygu Ozsoy Department of Environmental Engineering, Mersin University, Mersin 33343, Turkey
Abstract: Because of increasing environmental concerns/legislative pressure for plastics waste and rapid increases in the cost of petroleum, the development of “environmental friendly” materials has attracted extensive interest. Recently, bioplastics are one of the most innovative environmental friendly materials developed. Therefore, this paper will look at aspects of the bioplastics from the perspective of sustainability, advantages/disadvantages and standards. The global bioplastics market is thought to be growing at a rate of 20%~25% per year. They have some advantages such as lower carbon footprint, independence, energy efficiency, and eco-safety. However, they have some disadvantages such as high cost, recycling, reducing raw materials, misused of terms and lack of legislation. For the sustainability, recycling systems and production technology may be developed for bioplastics and by-product should be used for their production. Also, there is much standardization about them. It is important to have comparable international standard methods. Therefore, there is an urgent need to standardize all details. A new guide and standard for just bioplastics should be developed for production, usage and bioplastic waste management for every country in the world.
Key words: Advantages of bioplastics, bioplastics, disadvantages of bioplastics, standards, sustainability.
1. Introduction These GHGs (greenhouse gases) contribute to worldwide climate change [5]. The fourth problem is Plastic materials are currently considered very their “non-degradability or durability”. Plastic is not important materials due to their properties and biodegradable and will persist in the environment for performance over other materials such as metal and hundreds of years [6]. The economic problem is wood [1]. Worldwide annual plastics production is “competition for crude oil and energy security”. estimated to surpass 300 million tons by 2015 [2]. In recent years, these environmental/economic Because plastics are used in a wide range of problems and social concerns have triggered applications, economic and environmental problems developing environmental friendly materials such as have raised. bioplastics [7]. The first environmental problem which leads to Bioplastics are novel materials of the 21st century plastics is “landfill problem” [3]. Increasing amounts and would be of great importance to the materials of plastic waste emerged as a crisis in many areas of world [8]. Bioplastic production and consumption will the world because of shrinking landfill capacity, rising grow bigger in the future in the world. Because of this, costs and strong legislation. The second these materials need to be evaluated carefully for environmental problem is “accumulation of plastics in sustainability and waste management. Therefore, this oceans”. For example, in a long-term study in the review provides state of performance of bioplastics North Atlantic, one seawater sample contained the materials, focusing on benefits or disadvantages of equivalent of 580,000 pieces of plastic per square bioplastics. Also, it gives an overview of bioplastics kilometer [4]. Also, plastic incineration generates standards. toxic emissions such as carbon dioxide and methane. 2. What Is Bioplastic? Corresponding author: Ezgi Bezirhan Arikan, research assistant, research fields: waste management, industrial waste Generally, “bioplastic” are made from renewable management, bioplastics, and biodegrability of bioplastics. resources such as corn, sugars, potatoes, etc. [9] and E-mail: [email protected].
A Review: Investigation of Bioplastics 189 they are produced by a range of microorganisms [10]. and theoretically are biodegradable and compostable There are four types of degradable plastics: [1]. Since the plastics pyramid was developed, (1) Photodegradable bioplastics have light sensitive bioplastics are much further along in their commercial group incorporated directly into the backbone of the development. polymer as additives. Extensive ultraviolet radiation Packaging films and containers bioplastics are (several weeks to months) can disintegrate their particularly interesting, since most of these products polymeric structure rendering them open to further have a relative short service life and end up in bacterial degradation [6]; landfills. Biodegradable bioplastics have been found (2) The Business-NGO (non-government to possess wide range of properties, which find organization) Working Group for Safer Chemicals and application in biomedical field like making bone Sustainable Materials defines bio-based bioplastics as plates and screws, in drug delivery carriers and tissue “plastics in which 100% of the carbon is derived from engineering scaffolds [12, 14]. renewable agricultural and forestry resources such as Many countries around the world have already corn starch, soybean protein and cellulose” [1]; begun to integrate these materials into their (3) Compostable bioplastics are biologically technologies. In America, McDonald is making decomposed during a composting process at a similar biodegradable containers for their fast food. Other rate to other compostable materials and without companies such as Bayer, DuPont [15], Dow Cargill, leaving visible toxic remainders. In order to designate Nike, Danone, etc. are also producing biodegradable a plastic as bio-compostable, its total biodegradability, packaging. its disintegration degree, and the possible eco-toxicity The global bioplastics market is thought to be of the degraded material must be determined by growing about 20%~25% per year. Approximately means of standard tests [11]; 10%~15% bioplastics of the total plastics market will (4) Biodegradable bioplastics are fully degraded by increase its market share to 25%~30% by 2020. The microorganism without leaving visible toxic bioplastic market reached over 1 billion US$ in 2007 remainders. The term “biodegradable” refers to and it will be over 10 billion by 2020. More and more materials that can disintegrate or break down naturally companies are entering and investing in this market. into biogases and biomass (mostly carbon dioxide and 4. Biodegradation and Standardization of water) as a result of being exposed to a microbial Bioplastics environment and humidity, such as the ones found in soil, hence reducing plastic waste, whereas bio-based Biodegradability is an misused and abused sustainable materials. The fourth types of bioplastics term. Biodegradability results are strongly based are rather promising because of their actual utilization on test conditions such as humidity, temperature and by microorganism [6].
3. Bioplastic Market
Researchers have developed several tools to assist in decision-making about plastics selection. One of Avoid Prefer them is the “plastic spectrum” (Fig. 1) [12, 13]. Fig. 1 Plastics spectrum (PVC: polyvinyl chloride; PU: In this spectrum, bio-based bioplastics are at the polyurethane; PS: polystyrene; ABS: acrylonitrile right of the pyramid, indicating they are most butadiene styrene; PC: polycarbonate; PET: polyethylene preferable, as they are made from renewable resources, terephthalate; PE: polyethylene; PP: polypropylene) [13].
190 A Review: Investigation of Bioplastics microorganisms. Also, the nature is different from sequestration is reversed. But a permanent bioplastic, laboratory conditions. made to be similar to polyethylene or other
The list of some available biodegradation standards conventional plastics, stores the CO2 forever. Even if is considerable (Table 1) [3]. In the interests of the plastic is recycled many times, the CO2 environmental relevance, it is recommended that initially taken from the atmosphere remains selection of the test methodology be based on sequestered [16]; potential fields of application of the test polymer and Independence. Bioplastic is made from its end-of-life, which is compost, soil, fresh or marine renewable resources: corn, sugarcane, soy and other water. Some of the widely used standards are: plant sources as opposed to common plastics, which AS4736; ASTM D5338; ASTM D6002; EN 13432; are made from petroleum [17]; ISO 14855 (for compost exposure), ASTM D5988; Energy efficiency. Production uses less energy ISO 17556 (for soil exposure); ASTM D6691; ASTM than conventional plastics [16]. On the other hand, D6692; ISO 15314; and ISO 16221 (for marine plastics are made from about 4% of the oil that the exposure) [3]. world uses every year. With oil scarcity, the manufacture of plastics becomes increasingly exposed 5. Advantages and Disadvantages of to fluctuating prices [16]; Bioplastics Eco-safety. Bioplastic also generates fewer The future of biodegradable plastics shows great greenhouse gasses and contains no toxins. Yu and potential. Here are the advantages of bioplastics: Chen [17] reported that bioplastics contribute clearly Potentially, a much lower carbon footprint. It to the goal of mitigating GHG emissions with only should be pointed out that the carbon footprint of a 0.49 kg CO2 which is being emitted from production bioplastic is crucially dependent on whether the of 1 kg of resin. Compared with 2~3 kg CO2 of plastic permanently stores the carbon extracted from petrochemical counterparts, it is about 80% reduction the air by the growing plant. A plastic made from a of the global warming potential. biological source sequesters the CO2 captured by the However, possible problems might come along plant in the photosynthesis process. If the resulting with the use of bioplastics. Here are the disadvantages bioplastic degrades back into CO2 and water, this of bioplastics:
Table 1 List of some published standards for biodegradation of plastics [3]. Standard Description AS 4736-2006 Biodegradable plastics—biodegradable plastic suitable for composting and other microbial treatment Standard test method for determining the aerobic biodegradation of plastic materials in the presence of ASTM D5209-92 municipal sewage sludge Standard test method for determining aerobic biodegradation of plastic materials under controlled ASTM D5338-98 composting conditions Testing of compostability of plastics—Part 2: testing of the complete biodegradability of plastics in DIN V 54900-2 laboratory tests Requirements for packaging recoverable through composting and biodegradation—test scheme and EN 13432:2000 evaluation criteria for the final acceptance of packaging Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous ISO 14851:1999 medium—method by measuring the oxygen demand in a closed respirometer Methods for marine exposure ISO 16221:2001 water quality—guidance for the determination of ISO 15314:2004 biodegradability in the marine environment Plastics: biodegradable plastics in or on soil—recovery, disposal and (under approval) related CEN/TR 15822 environmental issues Biodegradable materials for use in agriculture and horticulture-mulching products—requirements and AFNOR NF U52-001 test methods
A Review: Investigation of Bioplastics 191
High costs. It is acclaimed that bioplastics costs There are a large number of tests which are used to two times more than conventional plastics. However, determine the degradation of bioplastics. It is the amount of large-scale industrial production of important to have comparable international standard bioplastics which are more common in the future with methods. Unfortunately, the current standards have the implementation of cost reduction is expected; not been equated to each other and tend to be used in Recycling problems. Bioplastic material might the countries where they originated. There is an urgent actually contaminate the recycling process if not need to standardize all details. A new guide and separated from conventional plastics. For example, standard just for bioplastics should develop for working with infrared rays in waste separation system, production, usage and bioplastic waste management bioplastics cannot be separated and the separating over the world. Also, labeling legislation may be plastics might be contaminated with bioplastics; improved based on a product’s raw material usage, Reducing raw materials. Bioplastics produced energy consumption, emissions from manufacture and from renewable sources might reduce raw material use. reserves. Moreover, in order to reduce energy Based on advantages of bioplastics, there are consumption during the production of bioplastics and certainly an abundant amount of materials and potential competition with agricultural resources for resources to create and find more uses for bioplastic. foods and also to provide additional raw material Based on disadvantages of bioplastics, for the sources, the exploitation of food by-products is also sustainability, several parameters must be considered, the current trend [18]; including the raw materials from which the bioplastic Misunderstanding of terms. The description of is generated, the energy consumed during bioplastic bioplastic as compostable can be confusing. All conversion and its life cycle assessment analysis from bioplastics are not compostable at home like organic production to ultimate disposal or recycle. food waste but usually require an industrial composting References treatment which is not available at every composting site [19]. Also, bioplastics and related terms are being [1] Alvarez-Chavez, C. R., Edwards, S., Moure-Eraso, R. L., misused by various manufacturers to place their and Geiser, K. 2011. “Sustainability of Bio-based Plastics: General Comparative Analysis and Recommendations for products more attractively on the market. Some slogans Improvement.” Journal of Cleaner Production 23 (1): used by manufacturers such as “environmental 46-7. friendly”, “non-toxic”, “degradable/totally degradable”, [2] Halden, R. U. 2010. “Plastics and Health Risks.” Annual are a trick with the uninformed and overwhelmed Review of Public Health 31: 179-94. [3] Philp, J. C., Ritchie, R. J., and Guy, K. 2013. “Biobased consumer; Plastics in a bioecOnomy.” Trends in Biotechnology 31 Lack of legislation. Production of bioplastics is (2): 65-7. projected to increase to over 6.7 million tons by the [4] Law, K. L. 2010. “Plastic Accumulation in the North year 2018 [20]. But still, many countries have not Atlantic Subtropical Gyre.” Science 329: 1185-8. [5] Barker, T. 2010. Technical Summary in Climate Change used any law or legislation about their production, 2007: Mitigation. Contribution of Working Group III to usage or waste management. the Fourth Assessment. Report of the intergovernmental panel on climate change. 6. Conclusions [6] El Kadi, S. 2010. Bioplastic Production form Inexpensive Sources Bacterial Biosynthesis, Cultivation System, This review has covered the bioplastics, their types, Production and Biodegrability. USA: VDM (Verlag Dr. degradability, standards, advantages and Müller) Publishing House. disadvantages. [7] Peelman, N., Ragaert, P., de Meulenaer, B., Adons, D.,
192 A Review: Investigation of Bioplastics
Peeters, R., Cardon, L., et al. 2013. “Application of [14] Sivan, A. 2011. “New Perspectives in Plastic Bioplastics for Food Packaging.” Trends in Food Science Biodegradation.” Current Opinion in Biotechnology 22: and Technology 32: 128-41. 422-6. [8] Mohanty, A. K., Misra, M., and Drzal, L. T. 2002. [15] Krzan, A., Hemjinda, S., Miertus, S., Corti, A., and “Sustainable Bio-composites from Renewable Resources: Chiellini, E. 2006. “Standardization and Certification in Opportunities and Challenges in the Green Materials the Area of Environmentally Degradable Plastics.” World.” Journal of Polymers and the Environment 10 Polymer Degradation and Stability 91: 2819-33. (1-2): 19-26. [16] Chen, Y. J. 2014. “Bioplastics and Their Role in [9] Karana, E. 2012. “Characterization of ‘Natural’ and Achieving Global Sustainability.” Journal of Chemical ‘High-Quality’ Materials to Improve Perception of and Pharmaceutical Research 6 (1): 226-31. Bioplastics.” Journal of Cleaner Production 37: 316-25. [17] Yu, J., and Chen, L. X. L. 2008. “The Greenhouse Gas [10] Luengo, J. M., Garcia, B., Sandoval, A., Naharro, G., and Emissions and Fossil Energy Requirement of Bioplastics Olivera, E. R. 2003. “Bioplastics from Microorganisms.” from Cradle to Gate of a Biomass Refinery.” Current Opinion in Microbiology 6: 251-60. Environmental Science and Technology 42: 6961-6. [11] Sarasa, J., Gracia, J. M., and Javierre, C. 2008. “Study of [18] Lagaron, J. M., and Lopez-Rubio, A. 2011. the Biodisintegration of a Bioplastic Material Waste.” “Nanotechnology for Bioplastics: Opportunities, Bioresource Technology 100: 3764-8. Challenges and Strategies.” Trends in Food Science and [12] Kaith, B. S., Jindal, R., Jana, A. K., and Maiti, M. 2010. Technology 22 (11): 611-7. “Development of Corn Starch Based Green Composites [19] Barker, M., and Safford, R. 2009. “Industrial Uses for Reinforced with Saccharum Spontaneum L Fiber and Crops: Markets for Bioplastics.” Accessed January 1, Graft Copolymers—Evaluation of Thermal, 2015. http://archive.hgca.com/publications/documents/ Physico-chemical and Mechanical Properties.” Bioplastics_web28409.pdf. Bioresource Technology 101: 6843-5. [20] European Bioplastics, Institute for Bioplastics and [13] Iles, A., and Martin, A. N. 2013. “Expanding Bioplastics Biocomposites, Nova-Institute. 2014. “Production Production: Sustainable Business Innovation in the Capacity.” Accessed January 1, 2015. Chemical Industry.” Journal of Cleaner Production 45: http://en.european-bioplastics.org/market/market-develop 38-49. ment/production-capacity/.
Journal of Civil Engineering and Architecture 9 (2015) 193-206 doi: 10.17265/1934-7359/2015.02.008 D DAVID PUBLISHING
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
Abdul Aziz Ansari1, Muhammad Aslam Bhutto2, Nadeem-ul-Karim Bhatti3 and Rafique Ahmed Memon4 1. Department of Civil Engineering, Mehran University of Engineering and Technology, Khairpur Mirs 66020, Pakistan 2. School of Built Environment, Heriot-Watt University Edinburgh, Edinburgh EH14 4AS, United Kingdom 3. Department of Civil Engineering, Quaid-e-Awam University College of Engineering Science and Technology, Larkano 77150, Pakistan 4. Gawader Sea port Authority, Gawader Sea Port, Gawader 91200, Pakistan
Abstract: Very high concentration of flexural, shear and torsional stresses occurs at the wall-slab junctions in a laterally loaded tall building consisting of planar walls and coupling slabs. Due to this concentration of stresses and their interaction, there are great chances of failure to occur at the junction. Also the flexural stresses are not uniformly distributed and have the highest intensity near the periphery of inner walls but are reduced drastically as we move away from the wall-slab junction. Numerous attempts have been made to strengthen the wall-slab junction by using various types of shear reinforcement to ensure that shear failure should not occur. Various methods including fibre reinforcement consisting of twins of twisted steel couplets have already been used. This paper describes a new method of placing 2 inch wide flange I-sections at appropriate locations to improve the shear strength of the wall-slab junctions. Based on systematic research, a new procedure has also been developed to assess the strength of wall-slab junction using the new reinforcement method. Test results showed that a substantial increase, up to 57%, in the shear strength of specimens was obtained by using the new method of shear reinforcement in a laterally loaded tall building.
Key words: Wall-slab junction, reinforcement, vertical steel bars, periphery of inner walls, I-section.
1. Introduction medium between pair of the cross-walls and is known as coupling slab. In this structural form, these floor The effect of wind and seismic loads becomes more slabs also act as diaphragm and distribute the pronounced with the increase in height of the building. horizontal loads to the vertical shear walls. The height In traditional system, the lateral stiffness to building is of storey can be kept up to a minimum level because provided by extending rigid structural frames within no false ceilings are required to hide the beams. fills serving the purpose of dividing the space. Perspective view of shear wall building is shown in In urban areas almost all over the world, the cost of Fig. 1. land is rapidly increasing. The rapid increase in the In the design of tall buildings, special consideration cost of land is influencing a common practice of tall has to be given for provision of the sufficient stability buildings. The tall buildings consist of load bearing in all directions against the lateral forces due to wind, RCC (reinforced cement concrete) cross-walls known earthquake or blast. The lateral forces produce critical as shear walls. The floor slab acts as a connecting stresses in the structure, set up vibrations in the structure and cause lateral sway, which could reach a Corresponding author: Abdul Aziz Ansari, Dr., professor, point of discomfort to the occupants. The shear walls research field: structural engineering. E-mail: [email protected]. resist the lateral loads on the structure by cantilever
194 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
C Transverse critical L section line of contraflexure of corridor opening
Fig. 2 Plan of a typical shear wall building showing the transverse critical section and line of contraflecture.
Memon and Narwani [5] presented the results of experimental behaviour of connecting beams in a laterally loaded shear wall building based on the Fig. 1 Perspective view of a shear wall building. results of first two models of a tall building tested by bending action, which produces rotations of the wall them. Rajkumar et al. [6] presented results of cross-section. The free bending of a pair of shear experimental behaviour of wall-slab joint in a laterally walls is resisted by the floor slab, which is forced to loaded shear wall building. Greeshma and Jaya [7] rotate and bend out-of-plane where it is rigidly studied the response of shear wall, floor slab connected with the walls. Due to the large depth of connection containing various types of shear shear wall, considerable differential shearing action is reinforcement when subjected to gravity and lateral imposed on the coupling slabs, which develop cyclic loading. The shear transfer coefficients for transverse reaction to resist the wall deformations. As modeling the wall and slab joint, are adopted a result, a non-uniform shear with very high intensity according to Wolanski [8]. However, there is a need to is developed in the slab along the line of contraflexure further investigate the problem and to strengthen the (roughly centre line of corridor opening) and wall-slab junction by using some new forms of the consequently unbalanced moments are induced along reinforcement. critical section of the slab with the highest The aim of the present research work is to concentrations at the inner face of wall, as shown in investigate the suitability and extent of increasing the Fig. 2. strength of the wall-slab junction using a new form of The non-uniform shear is ultimately transferred to vertical reinforcement consisting of the pieces of the 2 the wall at the junction. The torsional stresses are also inch wide flange rolled steel I-section as shown in induced in the slab along the sides of walls. The Fig. 3. interaction of all types of stresses makes the wall-slab The I-sections are placed in the slab around wall junction vulnerable. Mahmood [1] proposed a method periphery taking into consideration the location and to estimate the strength of junction by adjusting the the quantity of reinforcement as the major parameters. structural parameters and the material properties in The purpose is to avoid punching shear failure of high such a way that the induced system of stresses should, rise buildings consisting of in-plane cross shear walls under no circumstances, exceed the ultimate strength and coupling slabs subjected to lateral loads due to of junction. Attempts were made to increase the winds, etc.. strength of the junction by various means [2, 3]. The main objectives of the research are: (1) to Hossain [4] presented a paper on non-linear improve the shear strength of wall-slab junction by performance of slabs in coupled shear wall structures. providing new form of shear reinforcement in the slab
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a 195 Laterally Loaded Tall Shear Wall Building
T-section, but surely construction of such wall is too expensive and might not at all be required from applied loads point of view. Bari [2] used vertical stirrups but it is too difficult to accommodate such type of reinforcement. Fibre reinforcement used by Noor [3] poses mixing problem and since it is randomly placed a sense of uncertainty prevails about its placement at appropriate location and appropriate direction to impart maximum strength against the junction failure. The idea of using rolled steel I-section pieces attempted by Dilger et al. [10] showed the results that are encouraging in the case of flat slab-column connection. The idea has therefore been used in the present research to find its suitability for the wall-slab junction in a laterally loaded shear wall Fig. 3 Cross-sectional view of I-section. building. around the wall periphery; (2) to avoid the use of 3. Test Specimens vertical stirrups and the associated complications; (3) to find an economical and simpler form of shear Since it was deemed best to test specimens of real reinforcement; (4) to prepare a proper design criteria reinforced concrete of relatively large size so that the for wall-slab junction with new type of reinforcement. effect of size on the results could be minimized and let the behavior of specimens during the experimental 2. Critical Conclusions study corresponds to that of actual structure as close Mahmood [1] proposed a method to estimate the as possible, the dimensions as shown in Fig. 4 were strength of wall-slab junction but he did not attempt to adopted for the specimens. For these specimens, the strengthen it by using any form of reinforcement. non-dimensional structural parametric ratios are as Elnounu [9] used the wall configuration particularly follows:
300 mm 450 mm
100 mm 1,000 mm 830 mm 100 mm
430 mm 450 mm
400 mm 600 mm 400 mm 600 mm
1,000 mm 1,000 mm (a) (b) Fig. 4 Plan and elevation of the specimens showing dimension.
196 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
LW/XW = 0.6; was found to be enough, particularly from wall-slab
YW/XW = 0.5; junction strength point of view. t /W = 0.25; W W 4. Parameters of Study tW/WW = 0.1. where: The most important parameter considered in the
LW is corridor opening width; study was the quantity and location of the new form of
XW is over all width of the building; shear reinforcement. The quantity of shear
YW is bay width of connecting slab; reinforcement ranges from 0% to 0.97% of critical
tW is thickness of wall; section around the wall periphery while the location of
WW is width of wall. steel varies from 0.5d to d (effective depth of the slab). For the sake of economy, only one shear wall, a A typical shape of 12 mm wide piece of I-section used portion of slab cut along the central line of corridor as the new form of shear reinforcement is shown in opening, and the central lines of bay on both the sides Fig. 3. Table 1 gives the quantity, location and ratio of of the wall were taken as specimen for this new form of the shear reinforcement. experimental study. Fig. 5 shows the isometric view 5. Flexural Design of Slab of the specimen. The thickness of wall and slab and the width of bay, corridor opening and wall were For the flexural design of slabs, methods originally selected in such a way that the non-dimensional proposed by Hago [11] for common slabs and later structural parametric ratios remained within the adopted by Muhammad [12] for coupling slabs was practical range of such building. Although Mahmood followed. This method makes use of moment triads [1] adopted the slab thickness of 150 mm for his main obtained from elastic finite element analyses. With the series (MT (main test)), depending upon several help of Wood [13] and Armer [14] basic design factors, the slab thickness for this experimental study equations, the areas of steel required at different points was restricted to only 100 mm. The factors considered in making these selections were the capacity of the supporting arrangement of specimens and other practical difficulties, which might have manifested themselves due to excessive rigid body rotations caused by relatively more loads, which would have been required because of enhanced flexural strength of the slab if thickness of slab was to be 150 mm. However, the wall thickness, which was also 100 mm in this case as compared to 125 mm for MT series, Fig. 5 Isometric view of the specimen.
Table 1 Locations, quantities and ratios of new form of shear reinforcement. Serial No. Specimen No. Location of I-section No. of I-section Age of I-section (%) 1 SWSJWNR-01 - - 0.00 2 SWSJWNR-02 0.5d 11 0.74 3 SWSJWNR-03 0.5d 14 0.94 4 SWSJWNR-04 0.65d 14 0.88 5 SWSJWNR-05 d 14 0.79 6 SWSJWNR-06 d 17 0.79 SWSJWNR means strength of wall-slab junction with new form of shear reinforcement.
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a 197 Laterally Loaded Tall Shear Wall Building
3 within the slab were calculated by following the d Wd eff 3 recommendations of BSCP (British Standard Code of 2 w ddt 2 J ddtY c 6 12 1 w Practice) 8110 (1985) after removing all the factors of (4) safety. 2 d 2 2 WY eff d 2 6. Direct Ultimate Load Design Method calculate ultimate strength of the connection from: Unlike a steel structure, the strength of a concrete d b v b pc d structure can be tailored to match the required V u M Y b d (5) resistance at each point by providing just the required p1 1 α i amount of steel reinforcement. This suggests a way of V J c ultimate strength design of the reinforced concrete where: using elastic stress fields. This method is called direct Weff is effective wall width; ultimate load design method. tw is thickness of a planner shear wall;
vc is shear force transmitted through the 7. Strength of Wall-Slab Junction compression zone of concrete;
Wall-slab junction is probably the most sensitive fc is cylinder crushing strength of concrete; area of a shear wall structure. The failure of the vadd is increase in the value of critical shear stress junction will definitely be sudden, brittle, catastrophic due to increase of ratio of flexural steel above 1%; and without impending warning. This must be avoided vg is shear stress induced along critical section due at all costs. In fact, this might prove to be the to gravity load; controlling factor when it comes to the design of a αi is fraction of unbalanced moment transferred shear wall building. Mahmood [1] proposed a method from slab to column by torsion and eccentricity of to estimate the strength of connection for such shear; junctions and location of critical shear perimeter d is effective depth of the slab; around the wall periphery as shown in Fig. 6. The method is simple in nature but takes care of Critical section almost all the factors affecting the junction. Complete calculations regarding strength of connection of the specimen (SWSJWNR-01) of present study are presented as shown below: Y1 Weff calculate the effective length of wall (Weff):
11 1 tw Weff = 3tww t 23... (1) 22 2 Y2 calculate the critical shear stress vc from:
vc 0.33 c add vvf g (2) d/2
determine the value of factor αi from: 1 α i 1 (3) tw + d 2 dW 1 eff Critical section 3 t dw Fig. 6 Location of critical shear perimeter around the wall calculate the value of Jc from: periphery proposed by Mahmood [1].
198 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
Jc is a property of the critical perimeter analogous splitting tensile strength was taken as an average value to polar moment of inertia; of two 100 × 200 mm cylinders. Two cylinders were
Y1 is distance from centriod to Y2; used to determine the modulus of elasticity. Y is bay width + 3.5 t ; 2 w 8.2 Reinforcement Vu is ultimate shear transfer capacity of a connection; 8.2.1 Flexural Reinforcement in Slab
bp is the length of a perimeter at a distance 1.5 h For the flexural design of the slab, the loads were from column face; selected after making sure that the failure of the slab M is moment; itself would not occur. Accordingly, the slab was V is shear. reinforced with 12 mm dia tor steel bars placed at Using the above procedure, the ultimate loads/shear distance of 115 mm c/c (center to center) in both strengths of connection of all specimens were directions. The shear strength of the slab was also calculated adopting respective values of cylinder calculated by following the codal provisions and this crushing strength and are given in Table 2. was found to be much higher than expected strength of the connection even when reinforced with the new 8. Materials form of vertical reinforcement. Only two layers of 8.1 Concrete flexural steel bars were placed in the slab instead of four as in case of real buildings. Three samples of Concrete grade-30 with mean target compressive each type of steel bars were tested using Forney strength of 43 N/mm2 on 28 days curing was used to Universal Load Testing Machine and average yield cast all specimens. Because of the large quantity and as well as ultimate strength. which was needed for every specimen, concrete was 8.2.2 Wall Reinforcement prepared in batches. Ordinary Portland cement with Expectedly, the load at failure was to be higher than hill sand 10 mm uncrushed gravel was used for all the specimens tested by previous investigators. concrete mixes. The fine aggregate passed through No. Therefore, the wall was reinforced with eight 20 mm 16 sieve (ASTM (American Society for Testing and dia tor steel bars and 6 mm dia lateral ties were placed Materials)). Water/cement ratio was maintained at at average distance of 80 mm c/c. Fig. 7 shows 0.47 and it was allowed to mix 5 min to prepare the complete arrangement of reinforcement of the concrete of required consistency. For determination of specimens. strength properties of hardened concrete, 100 mm 8.2.3 New Form of Shear Reinforcement cubes and 100 × 200 mm cylinders were cast and New form of shear reinforcement was used at the cured with each specimen. All the cubes and cylinders critical section around the wall periphery in each were removed from the moulds 1 day after the casting. specimen with different locations and number of piece. The compressive strength of concrete was taken as an Fig. 8 shows the placement and quantity of 12 mm wide average of three 100 mm specimens and the cylinder pieces of I-section for specimens No. SWSJWNR-06. Table 2 Design load of the specimen.
Model No. No. of I-section Location of I-section Cylinder crushing strength Design ultimate load Vu (kN) SWSJWNR-01 Nil Nil 33.50 40.80 SWSJWNR-02 11 0.5d 31.97 39.80 SWSJWNR-03 14 0.5d 31.72 39.70 SWSJWNR-04 14 0.65d 32.48 43.40 SWSJWNR-05 14 d 33.97 52.50 SWSJWNR-06 17 d 33.82 52.40
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a 199 Laterally Loaded Tall Shear Wall Building
d = 86 mm 1,000 mm 1,000 mm
1,000 mm Fig. 8 Arrangement of reinforcement and location of I-section of the specimens SWSJWNR-06.
12 mm dia steel bar 1,000 mm welded at top Fig. 7 Arrangement of reinforcement of the specimens.
Three pieces of this I-section were welded with two steel bars pieces as shown in Fig. 9, and were tested by using ULTM (Universal Load Testing Machine) to determine experimentally yield strength of this new form of reinforcement. The results of this test are presented in Table 3.
9. Experimental Setup
9.1 Supporting Arrangement 12 mm dia steel bar Since, for the sake of economy, no base slab was welded at top cast, the specimen had to be positioned up-rightly Fig. 9 Pieces of I-section tested by universal testing at a proper location and held firmly to avoid rigid body machine.
200 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
Table 3 Yield stress and modulus of elasticity of I-section. Yield stress Ultimate stress Modulus of elasticity Serial No. Yield strain Age of elongation (%) (N/mm2) (N/mm2) (kN/mm2) 01 456.50 695.32 0.002000 228.25 7.98 02 412.55 711.12 0.001500 275.03 5.35 03 447.95 581.19 0.001500 286.92 2.67 Average 439.00 662.50 0.001666 263.40 5.32
hydraulic jacks each of 10 t capacity with a maximum extension of 140 mm were used for applying the load. Since, in the laboratory, there was no reaction floor hence beneath the jacks the ground was strengthened by constructing special foundation of RCC with only thin layer of concrete and plastered with thin coat of cement mortar, the possibility of sinking of the jacks in to the floor under load could be avoided. Although the uniform displacement of the line of contra flexure was achieved, for the sake of convenience, instead of imposing equal increment of displacements, the equal Fig. 10 Pictorial view of testing. increments of load were applied gradually. Dial rotation of specimen itself about its own wall edge gauges as well as transducers were used to measure and consequently creating stress concentration in the displacement at the central point of the loading these regions of wall leading to premature failure due beam of each specimen. to damage to the wall before reaching the ultimate 9.3 Displacement Measurement failure load of the wall-slab connection as desired. Based on the experience of first loading cycle of first An electrical displacement transducer was used to specimen, it was deemed essential to strengthen the record displacement. The transducer was installed at wall externally by providing confinement with the proper position with the help of an adjustable steel help of steel plates on all the four sides of the walls. stand and it was connected to an electronic display Photograph presented in Fig. 10 shows the pictorial system, which exhibited displacement in mm to an view of testing arrangement and supporting accuracy of 0.01 mm. Three dial-gauges in front, one arrangement used during this study while dimensioned at the back of the wall and two at the remote corners, details are shown in Fig. 11. were also placed. The dial gauges at the back of the wall were particularly used to measure the rigid body 9.2 Testing Arrangement rotation. Since the effect of lateral load was to be simulated 9.4 Load Measurement by the uniform displacement of the line of contra flexure, a hollow square steel section got fabricated by Two load cells of 100 kN capacity each coupled with welding 100 × 100 mm rolled steel angle sections all load cell amplifiers previously calibrated with the help the way through along their length. Two loading of universal load testing machine were used during points were identified and 100 mm thick plate was this study. The LCA (life cycle assessment) display welded there to avoid the local deformation because values in DVM (digital voltmeter) units, which are of concentration of load. Two manually operated then converted into kN from the calibration chart.
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a 201 Laterally Loaded Tall Shear Wall Building
Fig. 11 Dimensional details of supporting arrangement.
9.5 Strain Measurement 10. Test Procedure
Demec pads were stuck in pairs across the Initially, 5% of estimated ultimate load was applied transverse critical section and perpendicular to it and for a short time period and the specimen was unloaded. the central location. The strain was measured with Readings were taken of all the dial-gauges, transducer, demec gauge with an accuracy of 20 micro strains per load cell and strain for each of the specimens with no sub-division. Demec pads used were circular in shape load before starting the actual test. Care was taken to with 10 mm in diameter and 10 mm thick. For fixing see that the applied load was not causing any the demec pads, the concrete surface was first cleaned eccentricity and consequent twisting of the specimen. and made smooth by grinding using a grinding stone To allow for the overall deformation, creep, etc., the and then by fine sandpaper. Carbon tetrachloride was readings were taken 5 min after application of each used to remove the dirt and grease. Epoxy cement load increment and the possibility of crack formation adhesive (Drug A) and hardener (Drug B) mixture if any was observed. If there were any cracks formed, were applied to the cleaned surface and demec pads they were marked with a line and numbered at the tip were stuck on it by firmly pressing with thumb for by drawing a short cross line. The total time for each about 2 min. test was in the range of 4 h to 6 h. The strength
202 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building properties of the concrete were obtained by testing the of ultimate load. Clearly, this was also the shear cubes and cylinders on the day of testing each model. failure due to punching of wall through the slab. The failure occurred at a load of 53.04 kN. 11. Behavior of Specimens 11.3 Specimen SWSJWNR-03 11.1 Specimen SWSJWNR-01 (without New Form of Shear Reinforcement) Obviously, it was expected that the load bearing capacity of this specimen in terms of strength of For the first time, a hair-crack visible by naked eye junction would be higher than the previous specimen appeared at a load, which was 50% of ultimate load, due to increase of quantity of I-section pieces as 14 at the location of this crack is shown in Fig. 12a. As the the same location at 0.5d. This new form of shear loading progressed this crack widened and more crack reinforcement was 0.94% of the critical area around developed as shown in Fig. 12b. At about 80%, load the wall periphery. The ultimate load increased by cracking looks like that in Fig. 12c. The cracking only 7.7% than the previous. However, as expected, pattern just before failure is shown in Fig. 12d. the crack pattern and mode of failure resembled with Clearly, this was a case of junction failure. It can be the previous specimens. For the first time, hair crack observed from Fig. 12d that the wall punched through visible by naked eye at the bottom of the slab the slab. The failure was sudden, brittle and without appeared at 37% of ultimate load. Some more cracks impending warning. The failure occurred at the load appeared when the load reached at the 50% of of 44.1 kN. ultimate load. Several cracks at the top and bottom 11.2 Specimen SWSJWNR-02 developed at 82% of ultimate load. This was also the case of junction failure. The load at failure was Eleven I-section pieces are used as a new form of 57.12 kN. shear reinforcement at the critical section around the 11.4 Specimens SWSJWNR-04 wall periphery at a distance of 0.5d from the sides of wall, where d is effective depth of slab. The shear Same quantity of new form of shear reinforcement reinforcement used was 0.74% of the critical area (I-section) as that in the previous specimen (i.e., 14) around the wall periphery. The cracking appeared at was provided. This time the location of this 40% of the ultimate load. The cracking progressed as reinforcement was changed to 0.65d. This caused the the load increased. Several cracks appeared when the increase of the area around the wall periphery. load reached 70% of ultimate load. The cracks were Consequently, the ratio of shear reinforcement extended and widened when the load reached at 80% decreased to 0.88% of that of previous specimen. The
(a) (b) (c) (d) Fig. 12 Crack pattern of the slab: (a) at 50% of ultimate load; (b) at 70% of ultimate load; (c) at 80% of ultimate load; (d) at the load just before failure of model SWSJWNR-01.
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a 203 Laterally Loaded Tall Shear Wall Building
top and the bottom of the slab at 80% of ultimate load. Fig. 13 shows the crack pattern of the specimen. The load at failure was 67.32 kN.
11.6 Specimen SWSJWNR-06
Increasing the quantity of new form of reinforcement up to 17 pieces of I-sections at same location (i.e., d) as it was in specimen SWSJWNR-05, the 6th specimen was cast and tested. The mode of Top failure did not show much improvement with the increase of the quantity of this reinforcement which is 0.97% of the critical area around the wall periphery. The cracking of this specimen at the bottom was approximately similar to that of specimen SWSJWNR-05. The load at failure was 69.63 kN.
12. Discussion of Results
The most important observation regarding the behavior of specimens is the crack causing failure of Bottom Fig. 13 Crack pattern of the slab at top and bottom with the specimens. It appears from the experimental sides and back of the model SWSJWNR-05. evidence of this study that critical shear perimeter cracks just started at the bottom of the slab at 48% of shifts away from the sides of wall due to shifting of ultimate load. However, as expected, the mode of location of I-section piece used as new form of shear failure resembled with those of the previous reinforcement although the mode of failure was the specimens but cracking at the bottom showed same, i.e., punching of wall through the slab which is different pattern. Several cracks radiated in various the case of junction failure. Based on the test results, it direction from the inner face of the wall. However, the can be deduced that the shift of the critical perimeters specimen behaved more or less like previous should be taken into consideration because this would specimen. This was also the case of junction failure. give better estimation of the strength of wall-slab The load at failure was 63.6 kN. junction in case of new form of shear reinforcement. It is therefore recommended that the new location of 11.5 Specimen SWSJWNR-05 critical shear perimeter be taken at a distance of 0.75d This specimen was tested by maintaining the same instead of 0.5d. Hence, the estimation of wall-slab quantity of I-section piece as in specimen junction of laterally loaded shear wall building should SWSJWNR-04 (i.e., 14) at wider location up to d, be based on 0.75d instead of 0.5d, when this type of where d is effective depth of slab. new form of shear reinforcement is used. Fig. 14 The load at failure showed nominal improvement shows a comparison of the load-displacement due to change of location. The cracking of this relationship of all the test specimens. It is apparent specimen at the bottom was more or less similar to from the figure that ultimate load as well as the that of specimen SWSJWNR-04. Cracking started at displacement increase as the ratio of new shear
55% of ultimate load. Several cracks appeared at the reinforcement increases. The deformation becomes
204 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
Ultimate experimental load/designed (N) load
Displacement (mm) Fig. 14 Load-displacement relationship of all the models, i.e., SWSJWNR-01 to SWSJWNR-06. even more than 60% of the thickness of the slab itself junction originally proposed by Mahmood [1] has at failure of specimen SWSJWNR-06, containing been modified to take into account the additional maximum shear reinforcement. Clearly, this indicates component of strength imparted by this new form of that there would be excessive deflection of the slab in shear reinforcement. Here as expected, strain is quite real structures giving a warning that the failure would considerable when no new form of shear be imminent. Since the junction failures both in case reinforcement is added. Nevertheless, it decreases to of flat slabs and coupling slabs are sudden and brittle, its lowest value when the ratio of this special shear this excessive deflections before failure is a positive reinforcement is 0.88%. Obviously, this is due to the point. Increasing of shear reinforcement in specimens fact that bulk of stresses is born by the new form of showed further shifting of shear perimeter to a shear reinforcement. Similarly, situation is distance of d. encountered in case of compressive strain However, from the test results which include crack measured at various other locations in the slab. It is pattern, mode of failure, location of cracks causing obvious that in all the specimens the strain is the failure in the slab and their locations, it is suggested lowest in the slab along the critical section at the that the critical perimeter for junction failure around central point near the inner face of the wall. Several the wall periphery preferably be assumed to be at a other investigators have already reported this fact. The distance of 0.75d instead of d/2. It may be mentioned value is highest at second points from central here that, for slabs, the location of the critical shear locations. perimeter is assumed to be at a distance of d/2 by 13. Analysis of Results ACI-318 and 1.5h by CP8110. Based on the results, the method to estimate the strength of wall-slab The last column of Table 4 shows the average crack
Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a 205 Laterally Loaded Tall Shear Wall Building
Table 4 Comprehensive table showing all values of loads with a average crack location of the specimens. Experimental Design load Age difference Revised design Age difference Average crack Specimen No. No. of I-section ultimate load (N) (%) load (N) (%) location (mm) SWSJWNR-01 Nil 44.10 40.8 8.1 39.9 10.5 79 SWSJWNR-02 11 53.90 39.8 35.4 42.8 25.9 110 SWSJWNR-03 14 57.10 39.7 43.8 45.4 25.8 132 SWSJWNR-04 14 63.64 43.4 46.6 48.1 32.3 148 SWSJWNR-05 14 67.32 52.5 28.2 41.9 60.7 146 SWSJWNR-06 17 69.36 52.4 32.4 48.0 44.5 140
Table 5 Percentage increase of experimental ultimate load. Experimental ultimate load Ratio of ultimate load with Specimen No. No. of I-section Location of I-section (N) respect to Specimen 01 SWSJWNR-01 Nil Nil 44.1 - SWSJWNR-02 11 0.5d 53.90 1.22 SWSJWNR-03 14 0.5d 57.10 1.30 SWSJWNR-04 14 0.65d 63.64 1.44 SWSJWNR-05 14 d 67.32 1.52 SWSJWNR-06 17 d 69.36 1.57 location in millimeters from the side of the wall. From this study, it can be inferred that failure was During experimental study, it was observed that the governed by the strength of concrete and the steel shear crack causing the failure of first specimen was could play only limited role rather than controlling the averagely 79 mm away from the side of the wall. failure of the junction. The increase of I-section pieces However, this distance increased in the subsequent from specimens SWSJWNR-05 to SWSJWNR-06 specimen as the new form of shear reinforcement caused only a marginal increase of approximately 1.05 consisting of pieces of I-section was placed and times of the ultimate load. Therefore, further increase increased in the subsequent specimens. From Table 4, of this type of reinforcement may not be useful. The it can be observed that the change of location of ratio of shear reinforcement as percentage of the area I-section pieces was also changed from 0.5d to 0.65d of critical shear perimeter is only 0.97%. It is and finally to d. This seems to have affected the therefore recommended that the placement of this type location of cracks, which increase to a maximum of reinforcement must not be beyond 1%. However, value of 148 mm in case of specimen SWSJWNR-04. when the location of critical shear perimeter is Based on the results of this experimental work, it is assumed to be at a location of 0.75d instead of 0.5d, suggested that this type of shear reinforcement be the estimated strength as predicted by Memon and provided at distance of 0.75d from the wall. Table 4 Narwani’s method [5] will also be enhanced due to gives the details of experimental ultimate design loads, increase area. But substantial factor of safety would the initial design loads, the revised design load and the still exist. percentage difference for all the specimens. In all the 14. Conclusions cases, it can be observed that the experimental load is substantially higher than even the revised design loads, By using the new forms of shear reinforcement, the a maximum difference of 60.7% is reached in the case ultimate loads of specimens were increased by up to of specimen SWSJWNR-05. In Table 5, there is a 1.57 times compared to that of the control specimen. maximum increase of the load (with respect to However, for the design purpose, the increase in the specimen SWSJWNR-01 without shear reinforcement) ultimate load is limited to 1.50 times when new shear of 1.57 times in case of specimen SWSJWNR-06. reinforcement is provided to an extent of 1%.
206 Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building
A ratio of 0.88% of critical section for shear along Engineering at Quaid-e-Awam University of the wall periphery has been found to be optimum. Engineering Science and Technology, Nawabshah This new form of shear reinforcement should be (Sindh), Pakistan. The authors acknowledge the placed at a distance of 0.75d instead of 0.5d, where d support and assistance provided by the university. is effective depth of the slab. References The use of the new method of the shear reinforced [1] Mahmood, M. 1984. “Strength and Stiffness of Shear has shown a relatively ductile failure of the test Wall Floor Slab Connections.” Ph.D. thesis, University of specimen. At failure, the ratio of deflection of specimen Glasgow. to the slab thickness for the specimen SWSJWNR-06 [2] Bari, M. S. 1987. “Design of Shear Wall-Slab Connection was approximately twice, 60%, compared to that for Using Shear Reinforcement.” Ph.D. thesis, University of Glasgow. the control specimen SWSJWNR-01. [3] Noor, A. M. 2003. “Strength of Steel Fibre Reinforced Although the new form of shear reinforcement Concrete Shear Wall-Floor Slab Junction.” M.Phil thesis, shows a significant increase in the ultimate load of Mehran University of Engineering & Technology. [4] Hossain, K. M. 2003. “Nonlinear Performance of Slabs in wall-slab junction up to 57%, the full strength of steel Coupled Shear Wall Structures.” Advances in Structural shear reinforcement is not utilized. Engineering 6 (4): 339-52. A revised method of providing the shear [5] Memon, M., and Narwani, T. D. 2008. “Experimental reinforcement has been proposed by suggesting Investigations Regarding Behaviour of Tall Buildings Subjected to Lateral Loading.” Journal of Quality and amendments in the method developed by Memon and Technology Management 4 (1): 39-50. Narwani [5]. [6] Rajkumar, R. V., Greeshma, S., and Jaya, K. P. 2009. The ultimate loads of the specimens given by the “Parametric Investigation of Shear Wall-Floor Slab Connection.” In Proceedings of National Seminar on new method and those observed in the tests were in Performance of Disaster Resistant Structures, 35-42. reasonable agreement. [7] Greeshma, S., and Jaya, K. P. 2011. “Effect of Slab Shear reinforcement on the Performance of Shear wall-Floor 15. Significance of Research Slab Connection.” ASCE (American Society of Civil Engineers) Journal of Performance and Constructed Wall-slab junction is highly sensitive area of tall Facilitie 27 (4): 391-401. shear wall buildings where high concentration of [8] Wolanski, A. J. 2004. “Flexural Behavior of Reinforced stresses due to bending, shear and torsion are caused and Pre-stressed Concrete Beams Using Finite Element by lateral and gravity forces. This can lead to a Analysis.” M.Sc. thesis, Marquette University. [9] Elnounu, G. F. R. G. 1985. “Design of Shear Wall premature failure of tall shear wall buildings. Connections.” Ph.D. thesis, University of Glasgow. Although a significant amount of work has been [10] Dilger, W., Elmasri, M. Z., and Gali, A. 1978. “Flat Plats carried out in the area under research, more work is with Special Reinforcement Subject to Static Dynamics Moment Transfer.” Journal of American Concrete required in order to develop a definite design Institute (75-56): 543-75. procedure with more convenient and economical type [11] Hago, A. W. 1982. “Direct Design of Reinforced of shear/torsion reinforcement in terms of ratio vs. Concrete Slab.” Ph.D. thesis, University of Glasgow. economy. This aspect is under taken as part of [12] Muhammad, A. M. 1995. “Flexural Behaviour of Reinforced Concrete Coupling Slab in Shear Wall research program, the details of which are presented in Structures Subjected to Lateral Loads.” M.Phil thesis, this paper. Mehran University of Engineering and Technology. [13] Wood, R. H. 1968. “The Reinforcement of Slab in Acknowledgments Accordance with a Predetermined Field of Moment.” Concrete 2 (2): 319-20. The experimental work was carried out in the [14] Armer, G. S. T. 1968. “Contribution to Discussion on Ref. Structures Laboratory of the Department of Civil 34.” Concrete 2 (8): 319-20.
Journal of Civil Engineering and Architecture 9 (2015) 207-212 doi: 10.17265/1934-7359/2015.02.009 D DAVID PUBLISHING
Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand Sheets Bonded to Steel Beams
Masatsugu Nagai1, Yuya Hidekuma2, Takeshi Miyashita1, Yusuke Okuyama3, Akiya Kudo4 and Akira Kobayashi2 1. Department of Civil and Environmental Engineering, Nagaoka University of Technology, Niigata 940-2188, Japan 2. Infrastructure Use Division, Composites Company, Nippon Steel & Sumikin Materials Co., Ltd, Tokyo 103-0024, Japan 3. Department of Civil Engineering, National Institute of Technology, Nagano College, Nagano 381-8550, Japan 4. West Tokyo Operation Bureau, Metroportitan Expressway Co., Ltd, Tokyo 102-0093, Japan
Abstract: Corrosion of steel structures is unavoidable and the structural performance decreases dramatically due to the corrosion. As a repairing method for corroded steel members, bonding carbon fiber sheets with resin had been developed. The purpose of this study is to propose the flexural strengthening method for steel members by using CFRP (carbon fiber reinforced polymer) strand sheets. In order to clarify the stiffening effect and the debonding characteristics of CFRP strand sheets, and to optimize the strengthening design specifications, the flexural tests using high tension steel beams strengthened with CFRP strand sheets are performed. Two cases of experiments are carried out. In Experiment 1, the result from previous research is reflected in the strengthening design. Moreover in Experiment 2, the debonding characteristics obtained from Experiment 1 are reflected. As a result, it was clarified that CFRP strand sheets have stiffening effect equivalent to the theoretical value and its debonding property is practically high enough when FRP (fiber reinforcement polymer) sheets have an appropriate bonding length.
Key words: CFRP strand sheets, corrosion, debonding, flexural strengthening, steel members.
1. Introduction When using continuous fiber sheets, adhesion defects may be caused by poor impregnation of resin. When Corrosion of steel structures is unavoidable and the also using FRP strips, debonding may occur at lower structural performance decreases due to the corrosion. load because of interfacial shearing stress As a repairing method for corroded steel members of concentrated between steel and FRP at its tips [4]. which cross-sectional area is reduced, a method to In recent years, to solve these problems, the FRP bond the carbon fiber sheet with resin to steel strand sheet (Fig. 1) which consists of bunch of members has been studied [1]. This method is known individually hardened continuous fiber strands was as an efficient and economical method for repairing developed [4]. It is expected that no defects occur by because no heavy equipment is necessary at work site. using the FRP strand sheets because it is impregnated As for common reinforcing method, the continuous with resin and hardened at factory beforehand. fiber sheet [2] and the FRP (fiber reinforcement Furthermore, the FRP strand sheet can reduce polymer) strip [3] are being used. However, there necessary layers of a sheet compared to continuous exist some demerits on employing these materials. fiber sheets because of its high mass per unit area. The purpose of this study is to propose the flexural Corresponding author: Yuya Hidekuma, M.Sc., chief, research fields: composite materials, FRP strengthening of strengthening method for steel members by using CFRP metallic structures. E-mail: [email protected].
208 Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand Sheets Bonded to Steel Beams The material properties of CFRP strand sheets are listed in Table 1.
2.2 Outline of Tests
Two H-shaped steel girders are used to conduct flexural tests. CFRP strand sheets are bonded to lower flanges. The three-point loading tests are performed until yield load of steel (1,020 kN) or until debonding of CFRPs occurs. Measured values are deflection and strain in CFRP/steel. Debonding of CFRP is also observed. The experimental parameters are the Fig. 1 CFRP strand sheets. bonding length of each layer and the presence or
(carbon fiber reinforcement polymer) strand sheets. In absence of overlapped splice joint as listed in Table 2. order to clarify the stiffening effect and the debonding The specimens are shown in Fig. 3. F10B has four characteristics of CFRP strand sheets and to optimize overlapped splice joints from 1st layer to 3rd layer as the strengthening design specifications, the flexural shown in Fig. 3. The ply number of CFRP strand tests using high tension steel beams strengthened with sheets is 10 layers in Specimen F10A. Specimen CFRP strand sheets are performed. Two cases of F10B has 11 layers because the ply number becomes experiments are carried out. These experiments are one layer fewer at overlap splice joints. Therefore, the called Experiments 1 and 2, respectively. In stiffening effect of F10A and F10B should be the Experiment 1, the result from previous research [4] is same. reflected in the strengthening design. Moreover, in 2.3 Design Method Experiment 2, the debonding characteristics obtained from Experiment 1 are reflected. In this study, the The minimum bonding length of each layer for effects of the overlap splice joint (Fig. 2) of CFRP obtaining the theoretical stiffening effect can be strand sheets are also examined. calculated by following equations:
Ecf 2 2. Experiment 1 II si eAI cfcfcf (1) Es
2.1 Materials Steel As a base metal, SBHS700 (JIS G3128: high yield Overlap splice joints strength steel plates for welded structure) steel is used. Its yield stress is 836 MPa and elastic modulus is 200 GPa. The reason for using the high yield strength steel is to observe the debonding characteristics under large CFRP strand sheets Length of gap strain. CFRP strand sheets are used for reinforcements. Fig. 2 Schematic drawing of overlap splice joint.
Table 1 Material properties of CFRP strand sheets. Guaranteed value Mass per Design Measured value Sheet unit area thickness Elastic modulus Tensile strength Elastic modulus Tensile strength 2 (g/m ) (mm) (kN/mm2) (N/mm2) (kN/mm2) (N/mm2) Experiment 1 (SSHM900) 900 0.429 640 1,900 695 2,670 Experiment 2 (SSHM900) 900 0.429 640 1,900 721 2,970
Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand 209 Sheets Bonded to Steel Beams
Table 2 Parameters of Experiment 1. Length of 1st layer Length of overmost layer Length of step Length of gap Specimen Number of ply Number of joints (mm) (mm) (mm) (mm) F10A 10 2,360 920 80 0 - F10B 10 + 1 3,900 900 150 4 0
4,400 4,200
4,400 4,200
10@150 = 1,500 10@150 = 1,500 Fig. 3 Specimens of Experiment 1 (unit: mm).
2 m Ii1 to the structure. In previous research [4], that length xi (2) yi1Py was more than 100 mm. In this study, 200 mm is where: adopted as load transfer length. Therefore, the
Es, Ecf: elastic modulus of steel and CFRP; bonding length is further extended to 200 mm on one
Ii: geometrical moment of inertia of composite side. cross-section at ith layer; When strengthening steel members with CFRP,
Is, Icf: geometrical moment of inertia of steel and debonding of CFRP is the great concern. Normally, CFRP; the debonding occurs between the steel and the 1st
Acf: cross-sectional area of CFRP; layer of CFRP. Therefore, it is necessary to consider
yi: distance from neutral axis to optional location; debonding in designing the length of the 1st layer. In
ecf: distance from neutral axis to centroid of CFRP; previous research [4], steel stress at tip of the 1st layer
xi: position of end of ith layer of CFRP from the of the CFRP strand sheet is 280 MPa when debonding supporting point; occurs. Therefore, substituting 280 MPa into Eq. (2)
σm: stress of steel at the end of ith layer of CFRP; as σm yields the debonding load of 1st layer of CFRP.
Py: flexural load at center. In the case of F10A, the debonding of the 1st layer of
In this study, Py is 1,020 kN which is the yield load CFRP would occur at 780 kN. In the case of F10B, of the unreinforced steel and σm is 460 MPa which is the debonding would not occur because the length of the stress of reinforced steel at 1,020 kN. Substituting the 1st layer is extended to near supporting these values into Eq. (2) yields the minimum points where the bending moment is nearly 0. The bonding length of each layer. Normally, the load lengths of step in each layer of F10A and F10B are transfer length is necessary when bonding the CFRP the same.
210 Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand Sheets Bonded to Steel Beams
2.4 Results and Discussion correct. 2.4.2 Debonding Property 2.4.1 Stiffening Effect From Table 3, it is observed that the proposed The load-strain curves of F10A and F10B are design method regarding debonding property is not shown in Fig. 4. From this figure, it is found that the correct. In the case of F10A, the debonding occurred strains of the steel and the CFRP agree well with the between the 2nd and the 3rd layer of CFRP strand theoretical values in both specimens. Table 3 presents sheet, although the debonding load almost agrees with the experimental flexural rigidity (EIexp), theoretical that of designed value. In F10B, debonding also flexural rigidity (EIcal) and achievement ratio occurred between the 11th layer and the 10th layer. (EIexp/EIcal), and the fracture state at each load. The These results mean that the debonding at interlayer of theoretical flexural rigidities are calculated using CFRP needs to be considered in the design. Eq. (1). In this table, the achievement ratios of Table 4 presents the calculated value of the stresses flexural rigidities are almost 100% in spite of presence and strains of the steel and the CFRP strand sheet at or absence of the overlap splice joint. It means that the each fracture state. In this table, values of States proposed design method regarding stiffening effect is A1, B1 and B2 regarding the debonding are theoretical
1,100 1,100 1,000 1,000 900 900 800 800 700 700 600 600 Load (kN) Load (kN) 500 500 400 400 300 300 200 200 100 100 0 0 0 500 1,000 1,500 2,000 2,500 3,000 0 500 1,000 1,500 2,000 2,500 3,000 Strain (με) Strain (με) (a) (b) Fig. 4 The load-strain curves of: (a) F10A; (b) F10B.
Table 3 The results of Experiment 1. Flexural rigidity Specimen 2 2 Load (kN) Fracture state State No.* EIexp (kN·mm ) EIcal (kN·mm ) Achievement (%) 742 Debonding from 3rd layer A1 F10A 67,809 65,672 103.3 881 Tensile rupture at center A2 842 Debonding of 11th layer B1 F10B 68,752 65,672 104.7 873 Debonding of 10th layer B2 922 Tensile rupture at center B3 *Each fracture state is defined as A1, A2, B1, B2 and B3
Table 4 Calculated value of stress and strain in each fracture state. State Load Moment Stress of steel Strain of steel Stress of sheet Strain of sheet Specimen x (mm) No. (kN) i (kN·mm) (N/mm2) (με) (N/mm2) (με) A1 742 1,080 400,583 269 1,347 958 1,378 F10A A2 881 2,100 925,029 622 3,111 2,211 3,182 B1 842 1,650 694,502 313 1,563 1,221 1,757 F10B B2 873 1,500 654,615 309 1,547 1,191 1,714 B3 922 2,100 967,806 458 2,288 1,761 2,534
Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand 211 Sheets Bonded to Steel Beams
values at the end of debonding layer, as well as values The steel stress when debonding occurred at of state A2 and B3 regarding the tensile rupture of interlayer of CFRP was around 310 MPa; CFRP strand sheets are theoretical values at the center Several millimeters gap between the CFRP of span. The steel stress of state B1 agrees with that of strand sheets is required at overlap splice joint. state B2. The steel stress of state A1 should agree as In Experiment 2, these findings are reflected to the well. However, the result shows that they are lower design method. The steel stress, when debonding than those of B1 and B2. In F10A, the rapid load occurs at interlayer of CFRP, is decided as 300 MPa. transfer occurs near the vertical stiffening plate. This The gap length between the CFRP strand sheets is causes the occurrence of debonding at lower stress in also decided as 20 mm, which takes into consideration F10A. It should be noted that the debonding of CFRP of the fabrication error. The experimental parameters is likely to occur near the stiffening plate. The results are listed in Table 5. F10D has five overlap splice from F10B reveal that the steel stress is about 310 joints from the 1st layer to the 4th layer. In the case of MPa when debonding occurs at interlayer of CFRP. F10C, the length of the 1st layer is designed upon the In Table 4, it is found that the CFRP stress of state assumption that debonding would occur at 650 kN and B3 is lower than that of A2. The tensile strength in the other layer is designed upon the assumption that F10B is lower than the guaranteed tensile strength of debonding would not occur until 650 kN. In the case CFRP although the tensile strength in F10A is higher of F10D, no fracture would occur until 1,020 kN. than that of CFRP. It can be considered that the reason of the tensile strength reduction is the stress 3.2 Results and Discussion concentration at the overlap splice joint. Therefore, a Table 6 presents the experimental flexural rigidity, gap of several millimeters between the CFRP strand the theoretical flexural rigidity, the achievement ratio sheets is required at overlap splice joint in order to and the fracture state. The theoretical flexural reduce the stress concentration. rigidities are calculated using Eq. (1). In this table, the 3. Experiment 2 achievement ratios of flexural rigidities are almost 100%. From Table 6, it is found that the fracture 3.1 Outline of Tests modes of F10C and F10D agree with the assumption The findings from Experiment 1 are as follows: based on the proposed design method. The debonding In previous research, the steel stress at tip of 1st load of F10C is 815 kN, which is higher than designed layer of which debonding of CFRP strand sheet value. The steel stress at tip of the 1st layer of which occurred was 280 MPa; debonding of CFRP strand sheet occurred is 350 MPa.
Table 5 Parameters of Experiment 2. Specimen Number of ply Length of 1st layer Length of overmost layer Length of step Number of Length of gap (mm) (mm) (mm) (mm) joints F10C 10 2,000 740 70 0 - F10D 10 + 1 3,900 1,600 115 5 20
Table 6 Results of Experiment 2. Flexural rigidity Load Specimen 2 2 Fracture state EIexp (kN·mm ) EIcal (kN·mm ) Achievement (%) (kN) F10C 66,700 66,171 100.8 815 Debonding from the 1st layer F10D 68,594 66,171 103.7 - No fracture
212 Bonding Characteristics and Flexural Stiffening Effect of Carbon Fibre Reinforced Plastics Strand Sheets Bonded to Steel Beams
This value is higher than that of the previous research. (4) A 20 mm gap between the CFRP strand sheets However, in this study, the steel stress when the is required at overlap splice joint; debonding occurs at tip of the 1st layer of CFRP (5) The flexural test results of the specimens, which strand sheet is decided as 280 MPa in consideration of were designed based on the above findings, exactly safety. In the case of F10D, the debonding at agreed with the designed value. Hence, in order to interlayer of CFRP strand sheet and the rupture of establish the optimal flexural design method for steel strand sheet at joint did not occur until 1,020 kN. It members using CFRP strand sheets, it is important to means that the proposed design methods regarding consider and reflect in design of these results. debonding at interlayer of CFRP and gap between References strand sheets at joint are correct. [1] Cadei, J. M. C., Stratford, T. J., Hollaway, L. C., and 4. Conclusions Duckett, W. G. 2004. Strengthening Metallic Structures Using Externally Bonded Fibre-Reinforced Polymers. In order to clarify the stiffening effect and London: CIRIA (Construction Industry Research and debonding characteristics of CFRP strand sheets and Information Association) Publication. to optimize the strengthening design specifications, [2] Sugiura, H., Kobayashi, A., Inada, N., Honma, A., Ohgaki, K., and Nagai, M. 2009. “A Proposal of Design the flexural tests, using high strength steel beams and Construction Method of Repair for Corroded Steel strengthened with CFRP strand sheets, were Member by Carbon Fiber Sheets.” Journal of performed. The results obtained from this research are Construction Management and Engineering 65 (1): summarized as follows: 106-18. [3] Lenwari, A., Thepdhatri, T., and Albrecht, P. 2006. (1) The steel beam strengthened with CFRP strand “Debonding Strength of Steel Beams Strengthened with sheets can be designed as composite cross section; CFRP Plates.” Journal of Composites for Construction 10 (2) The steel stress at the tip of the 1st layer of (1): 69-78. which debonding of CFRP strand sheet occurred was [4] Hidekuma, Y., Kobayashi, A., Tateishi, A., Nagai, M., and Miyashita, T. 2010. “Repairing Method for the Steel 280 MPa; Members by CFRP Strand Sheets.” In Proceedings of the (3) The steel stress when the debonding occurred at 5th International Conference on FRP Composites in Civil interlayer of CFRP strand sheet was 310 MPa; Engineering, 881-5.
Journal of Civil Engineering and Architecture 9 (2015) 213-224 doi: 10.17265/1934-7359/2015.02.010 D DAVID PUBLISHING
Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures
Nobuaki Otsuki1, Akiyuki Shimizu2 and Toshiro Kamada3 1. Department of International Development Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Japan 2. Department of Architecture, Tokyo University of Science, Niijuku 6-3-1, Japan 3. Division of Global Architecture, Osaka University, Yamadaoka 2-1, Japan
Abstract: There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cracks are almost harmless. So, a good guideline regarding how to deal with cracks in concrete structures is needed. In this guideline, the practical investigation, repair and strengthening method of cracked concrete structures is discussed. And the detecting subjects are cracks generated immediately after casting and during the service time. This guideline targets on the owners (including managers) of concrete structure and the engineers working for the maintenance of concrete structure. JCI (Japan Concrete Institute) published first version of “Practical Guideline for Investigation and Repair of Cracked Concrete Structures” in 1980, and then the fourth version titled “Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures—2009” was published. This guideline is very practical when cracks are observed in existing concrete structures, in any other countries as well as in Japan. These three authors led the establishment of this guideline.
Key words: Crack, concrete structure, investigation, repair, strengthening.
1. Introduction the engineers who are working for investigation, cause estimation, evaluation, judgment, repairing and The scope and object of this guideline are as follows: strengthening of cracked concrete structures are
(1) This guideline covers the practicable included. investigation of cracked concrete members (structures), The most significant feature of this guideline is that causes of cracking, evaluation, judgment of the the main users of this guideline are from a beginner to a necessity of strengthening, selection of the most middle career engineer who is in charge of a structure effective repair and strengthening method. This for maintenance and takes actions if there are cracks in guideline mainly applies to in-situ cast concrete the concrete structures or members. Therefore, this structures; guideline is prepared in a simple way for easy learning (2) This guideline covers the cracks generated in a and application of the learned knowledge in concerned structure immediately after casting and during the structures. This guideline systematically describes the service period; process of investigation (Section 2), cause estimation (3) The main targets of this guideline are the owners (Section 3), evaluation (Section 4), judgment (Section (including managers) of the concerned structures. Also, 5) and repair and strengthening (Section 6). A flow diagram of the general procedure of this Corresponding author: Nobuaki Otsuki, Dr. Eng., guideline from investigation to repair and professor, research field: concrete engineering. E-mail: [email protected]. strengthening [1] is shown in Fig. 1. Strictly speaking,
214 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures
Identification of crack
Standard investigation for cause estimation (Section 2.2)
Detailed investigation for cause estimation (Section 2.3)
Can it be estimated No the cause of cracking? Investigation for evaluation (when it is necessary)
Yes
The cause estimation (Section 3.3) Additional investigation for repair and (when detailed investigation was conducted (Section 3.4)) strengthening (Section 6.2.3) (mainly, investigation such as construction environment, amount and range, etc.) Selection of type of estimation (Section 4.1)
Evaluation (Sections 4.2, 4.3 and 4.4)*
Judgment (Section 5)*
Repair and strengthening (Section 6) Fig. 1 Procedure from the investigation of cracks to the application of repair and strengthening. * in the flow means that the evaluation and judgment method are different by the selection of Evaluation-I, Evaluation-II and Evaluation-III. this procedure could not correspond to some situations enables not only to predict the cause of cracks but also while this flow diagram shows a standard procedure to select suitable methods of repair and strengthening. that can correspond to most of the cracks. Also, “investigation” is divided into two steps, such as “standard investigation” and “detailed 2. Investigation investigation”. Standard investigation must be carried 2.1 General out as the preliminary investigation. The detailed investigation should be carried out in the case that The objective and the types of investigation are as cause estimation of cracks, repair and strengthening follows: cannot be performed based on the standard (1) The main objective of investigation is to collect investigation. data for the estimation of the causes of cracking of a structure or its members. These data are also necessary 2.2 Standard Investigation for subsequent evaluation of cracks, judgment of the Standard investigation is carried out by investigating necessity of repair and strengthening; the documents and visual inspection of structures. (2) There are two types of investigation, such as Standard investigation is carried out in the standard investigation and detailed investigation. preliminary stage before estimating the causes of Investigation described in this guideline is the cracking followed by the repair and strengthening plan, beginning step for cause estimation, evaluation of as outlined in the flow diagram related to the approach cracks and a selection of repair and strengthening. to the investigation, repair and strengthening in Fig. 1. Information based on the appropriate investigation The standard investigation includes investigation of
Introduction of a Japan Concrete Institute Guideline: Practical Guideline for 215 Investigation, Repair and Strengthening of Cracked Concrete Structures documents and observation of the structures. The per the budget and also time constraint. Detailed investigation of documents is carried out to estimate investigation is divided into on-site investigation and the cause of cracks of the member (structures) by laboratory investigation. On-site investigation includes collecting the information of the structures, geological investigations of materials used in the structure, condition and ground condition with naked eye and/or loadings on the structure, environmental conditions of using simple tools. The standard investigation is the structure, foundation condition, structural limited to basic investigations that can be done very performance, deformation and vibration of the quickly without any experiments or long-term structure. On the other hand, laboratory investigation is observation. In some cases, drying shrinkage cracks performed based on the symptoms of deterioration. The will be estimated by the standard investigation. In this detailed investigation should be carried out on some case, drying shrinkage cracks can be evaluated as selected items and hence will not be covered with all Evaluation-I defined in Section 4.1, which can be items described in this section. The results of followed by an easy judgment of repair and laboratory investigation will contribute significantly to strengthening. the judgment of an expert engineer. Hence, the items to The investigation of documents includes the be investigated in the laboratory should be discussed investigation of engineering drawings, design report with an expert engineer prior to the laboratory and specification, construction record, history of past investigation. Investigation will significantly investigation, repair and strengthening, service load contribute to the judgment of an expert engineer. Hence, condition, climate condition, geographical condition, the items to be investigated in the laboratory should be ground condition, etc.. The observation of structures discussed with an expert engineer prior to the includes the investigation of the situation of cracks, laboratory investigation. inconvenience due to cracks, other phenomena such as 3. Cause Estimation peeling of concrete, unusual vibration, etc.. 3.1 General 2.3 Detailed Investigation As described in Section 1, this guideline evaluates Detailed investigation is carried out in cases when the crack based on its cause, followed by judgment of the estimation of the causes of cracking is not possible necessity for repair and strengthening and their within the scope of standard investigation. The detailed selection. The cause estimation of crack is a starting investigation is divided into on-site investigation and point of this flow. This section proposes a method to laboratory test. estimate the cause of crack and to obtain data for Detailed investigation should be carried out evaluation of crack, judgment of the necessity for according to the flow chart shown in Fig. 1 in the case repair and strengthening, and their selection. that the cause of crack is difficult to estimate based on The causes of cracks are determined based on the the results of the standard investigation. The detailed standard investigation as explained in Section 2.2. investigation is performed with special equipment However, if the results of standard investigation are while the standard investigation is done by simple tools. insufficient to judge the causes of cracking, detailed The detailed investigation is more expensive and needs investigation is carried out according to the detailed longer period than the standard investigation. Hence, investigation described in Section 3.4. the purpose of the detailed investigation must be fixed 3.2 Causes of Cracking before planning the detailed investigation and also the number of the specimens to be tested must be fixed as There are many causes of the cracking. Those that
216 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures
Table 1 Causes of cracking. Major classification Sub classification Sub-sub Number Cause A1 False setting of cement Cement A2 Heat of hydration of cement A3 Abnormal expansion of cement Used materials A4 Clay inclusion in aggregate Aggregate A5 Low quality aggregate A Materials A6 Reactive aggregate (alkali-aggregate reaction) A7 Chloride in concrete A8 Settlement and bleeding of concrete Concrete - A9 Drying shrinkage of concrete A10 Autogeneous shrinkage of concrete B1 Non-uniform dispersion of admixture Mixing B2 Long-time mixing B3 Change of mix proportion at pumping Transport and placing B4 Inappropriate placing sequence B5 Rapid placing Concrete Compaction B6 Inappropriate compaction B7 Loading or vibration before hardening Curing B8 Rapid drying during initial curing B9 Early age frost damage B Construction Construction joint B10 Inappropriate joint treatment B11 Inappropriate placement of reinforcement Steel Arrangement of steel B12 Lack of cover B13 Deformation of formwork Formwork B14 Water leakage (from formwork, into subgrade) Formwork B15 Early removal of formwork Support B16 Settlement of support Cold joint B17 Inappropriate joint or discontinuity Others PC grout B18 Insufficient grouting C1 Change of environmental temperature and/or humidity Difference of temperatures and humidity between two C2 Temperature and surfaces of member Physical humidity C3 Repeated cycles of freezing and thawing C Environment C4 Fire damage C5 Surface heating C6 Chemical reaction of acid and/or salt Chemical Chemical reaction C7 Corrosion of embedded steel due to carbonation C8 Corrosion of embedded steel due to chloride attack D1 Long-term load within design load Long-term load D2 Long-term load over design load Load D3 Short-term load within design load D Structure and Short-term load D4 Short-term load over design load external force D5 Insufficient cross sectional area or quantity of steel Structural design - D6 Differential settlement of structure Support condition - D7 Freezing heave E Others - - - Others
Introduction of a Japan Concrete Institute Guideline: Practical Guideline for 217 Investigation, Repair and Strengthening of Cracked Concrete Structures
are generally observed in practice are listed in Table 1. systematically followed to identify the probable causes of crack. In Category (1), the cause is roughly 3.3 Cause Estimation Based on Standard Investigation estimated based on the major Classifications A to D Cause estimation is performed by comparing the described in Table 1. Taking into consideration the results of the standard investigation with Table 1. crack patterns (generation period, regularity, extent),
Standard investigation described in Section 2 mainly deformation associated with the structure, limit of consists of visual observation of cracks, and structure affecting the deformation, mixture investigations of previous records and failures. proportions and environmental conditions, the causes There are many cases for which the cause can be of cracking are further classified as A1 to A10, B1 to estimated by standard investigation. B18, C1 to C8 and D1 to D7 in each of Categories (2) For example, in many cases, the cause estimation to (4) (Tables 2 to 5) : will fall under the major classification materials (1) major classifications of causes (Table1): described in Table 1. In some cases, it may not be materials (A); possible to evaluate the exact cause from the results of construction (B); the standard investigation, but some rough evaluations service environment (C); may be made from the standard investigations that can structure and external force (D); be useful during detailed investigation. (2) classification based on generation period, Procedure for cause estimation of crack—for beginners—shall be carried out according to the regularity and extent of cracks (Table 2): procedure Sections 3.3.1 to 3.3.3. generation period (several hours to one day, a few 3.3.1 Classification of Cracks days, several 10 s of days); The following four Categories (1) to (4) must be regularity (yes or no);
Table 2 Classifications based on the generation period, regularity and extent of cracks. Pattern of cracks Cause estimation Generation period Regularity Extent Reticular B2, B3 Yes Surface layer A8, B2, B3, B5, B14, B16, B17 Penetration B2, B3, B4, B10, B16, B17 Few hours to one day Reticular B8 No Surface layer A1, B5, B7, B8, B13, B17 Penetration B4, B10, B17 Reticular Yes Surface layer A2, A10, B15, D5 Penetration A2, A10, B16 Few days Reticular A4, B9 No Surface layer B7, B9 Penetration Reticular A6, A9, B2, B3, D2 Yes Surface layer A6, A7, A9, A10, B2, B3, B11, B12, C1, C2, C7, C8, D1, D3, D5 Penetration A9, A10, B2, B3, B4, B10, B18, C1, D2, D4, D5, D6 More than several ten days*1,*2 Reticular A3, A4, A6, B1, B9, C3, C4, C5, C6 No Surface layer A3, A4, A5, A6, B9, C3, C4, C5, C6, D7 Penetration B4, B10, B18, D6 *1Cracks form after development of required strength; *2if fatigue is the cause of cracking (D1 and D2), the generating period must be at least from few years to multiple of few 10-year.
218 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures
Table 3 Classification based on the deformation and limits of consideration. Deformation factors of concrete Limit of consideration*3 Cause estimation Material A1, A2, A4, A9, A10, B1, C1, C3, C4, C5 Shrinkage*1 Member A2, A9, A10, B2, B3, B8, B14, B15, B17, B1, C2, C3, C4, C5 Structure A9, B2, B3, B8, B15, C1, C2, C3, C4, C5 Material A3, A5, A6, B1, C1, C3, C4, C5, C6 Expansion*2 Member A7, B1, B12, B18, C1, C2, C3, C4, C5, C7, C8 Structure A7, C1, C4, C5 Material A5, A5, C1 A8, B4, B5, B6, B7, B9, B10, B11, B12, B13, B16, B17, C1, C2, D1, Settlement, bending and shearing Member D2, D3, D4, D5, D6, D7 Structure B6, C1, D1, D2, D3, D4, D6, D7 *The cracked region shows the occurrence of shrinkage; *2the crack region shows the occurrence of expansion; *3material: it is required to investigate materials for cause estimation (mainly concrete); member: it is required to investigate members, such as beam, column, wall, slab, etc. for cause estimation; structure: it is required to investigate the whole structure (including roof and foundation) for cause estimation.
Table 4 Classifications based on mixture proportion. Mixture proportion Cause estimation Standard Rich A2, A6, A9, A10 Cement content per unit volume of concrete is more than 350 kg/m3 Poor A8, C3, C6, C7, C8 Cement content per unit volume of concrete is less than 270 kg/m3
Table 5 Classifications based on weather condition during placing concrete. Weather condition at the Cause estimation Standard placing of concrete The daily men temperature during placing is higher than 25 °C, and the High temperature A2, B2, B8, B17 ambient temperature at placement is higher than 25 °C Low temperature A8, B7, B9, B13, B16, D7 The daily mean temperature at placing is lower than 4 °C Low humidity A4, A9, B8, B17 The humidity is lower than 60%
extent (reticular, surface layer, and penetration). (4) classifications based on mixture proportions and The extent of cracks is defined as reticular for mesh weather conditions (Tables 4 and 5)： type cracking, as surface layer if the depth of the cracks mixture proportion (rich and poor); is limited to the surface region of the structure, and as weather conditions during placing of concrete penetration if the cracks continue through the section. (high or low temperature, and low humidity). (3) classification based on deformation and limit of 3.3.2 Detection of Common Causes consideration (Table 3): The common causes of cracking are identified by deformation of concrete (drying shrinkage, comparing the results of the investigations summarized expansion, settlement, bending, and shearing); in Categories (1) to (4). The non-matching causes of limit of consideration (materials, member, and Categories (1) to (4) are excluded for simplicity. structure). 3.3.3 Cause Estimation Based on Standard If the deformation is associated with the material of Investigation the structure, then the limit of consideration is defined Cause estimation should be performed based on the as materials: if it is associated with a particular results of the detailed investigation explained in member of the structure, then the limit of consideration Section 3.4 if cause estimation cannot be performed is defined as member, and if it is associated with the based on the results of the standard investigation. whole structure, then the limit of consideration is If it is difficult to evaluate the cause from the results defined as structure. of the standard investigation, which is performed as per
Introduction of a Japan Concrete Institute Guideline: Practical Guideline for 219 Investigation, Repair and Strengthening of Cracked Concrete Structures
Section 3.4. construction. 4.1.3 Evaluation-III (Applied for Cracks Due to 3.4 Cause Estimation Based on Detailed Investigation Combined Deterioration, etc.) If it is difficult to perform cause estimation from the The targeted cracks in this classification are cracks results of standard investigation, cause estimation that could not be classified into Evaluation-I and should be performed based on the results of detailed Evaluation-II, and/or could decrease the structural investigation, as explained in Fig. 1. performance. This evaluation should be done by the experts and may be used at the cases in which owners 4. Evaluation of Cracks would like to use the structures for a very long time 4.1 General (more than 20 years), or when the crack causes serious damage at the condition of supports and load carrying In this guideline, “evaluation” is defined as an influence of cracking to concrete by using the data capacity of the member (or structure). from investigation and cause estimation. Moreover in The type of evaluation of cracks should be chosen this guideline, evaluation type defined after based on Table 6 in accordance with the results of considering the influence of the crack can be changed investigation and estimation of causes of cracks, and by the cause of cracking. In a word, cracking can be evaluation is carried out by the methods shown in classified as three types as follows, after the cause Sections 4.2 to 4.4. The procedure of evaluation is estimation. explained in Fig. 2. 4.1.1 Evaluation-I (Applied for Dry Shrinkage 4.2 Evaluation-I (Applied for Drying Shrinkage Cracks Cracks, etc.) and So on) The targeted cracks in this classification are cracks that will stop growing within several years after placing In Evaluation-I, the grade of influence of crack on the concrete. Also, these cracks themselves are not performances of the member is expressed as large, immediately responsible for corrosion. However, from medium and small, when the required performance is cracks water, oxygen and/or chloride ions may the resistance against steel corrosion and water leakage. penetrate and cracks indirectly cause corrosion of steel In the case of the evaluation of durability resistance bars. So, the drying shrinkage and temperature cracks against steel corrosion, Evaluation-I uses Table 7. Crack are classified in this group. At Evaluation-I, the width means the width at surface of the member. durability of corrosion of steel bars and waterproof In the case of the evaluation of durability resistance property are considered related to the kind of against water leakage, Evaluation-I uses Table 8. environment. It is evaluated with the width of the crack Penetrate crack is applicable. The crack width when at the time of the investigation or the repair is means the width of the crack on the surface of the executed. member. 4.1.2 Evaluation-II (Applied for Cracks Due to 4.3 Evaluation-II (Applied for Cracks Due to Chloride Chloride Attack, Carbonation, etc.) Attacks and Carbonation, etc.) The targeted cracks in this classification are cracks that continue to grow once started. However, the In Evaluation-II, the grade of influence of crack to progress or growing of the cracks can be somehow the performances of the member is expressed as large, estimated. Chloride attack and carbonation cracks are medium, and small, the same as in the case of classified in this group. This type of crack occurs Evaluation-I, resistance to steel corrosion or concrete several years later from the completion time of degradation.
220 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures
Table 6 Causes of cracks and types of evaluation. Type of evaluation No. Predicted causes I II III A1 False setting of cement ○ A2 Heat of hydration of cement ○ ○ A3 Abnormal expansion of cement ○ A4 Mud included in aggregate ○ ○ A5 Low quality aggregate ○ ○ A6 Reactive aggregate ○ ○ A7 Chloride in concrete ○ ○ A8 Settlement and bleeding of concrete ○ ○ A9 Drying shrinkage of concrete ○ ○ A10 Autogeneous shrinkage ○ ○ B1 Non-uniform dispersion of admixture ○ ○ B2 Long-time mixing ○ ○ B3 Inappropriate change of proportion at pumping ○ ○ B4 Inappropriate placing sequence ○ ○ B5 Rapid placing ○ ○ B6 Inappropriate compaction ○ ○ B7 Loading or vibration before hardening ○ B8 Rapid drying during initial curing ○ ○ B9 Early age frost damage ○ ○ B10 Inappropriate joint treatment ○ ○ B11 Bad placement of rebar ○ ○ B12 Lack of cover ○ ○ B13 Deformation of formwork ○ ○ B14 Water leakage from formwork ○ ○ B15 Early removal of formwork ○ ○ B16 Settlement of support ○ ○ B17 Inappropriate joint of discontinuity ○ ○ B18 Insufficient grouting ○ C1 Change of environmental temperature and/or humidity ○ ○ C2 Difference in temperature or humidity of both sides ○ C3 Repeated cycles of freezing and thawing ○ ○ C4 Fire ○ C5 Surface heating ○ C6 Chemical reaction of acid and salt with chloride ○ ○ C7 Corrosion of embedded rebar due to carbonation ○ ○ C8 Corrosion of embedded rebar due to chloride attack ○ ○ D1 Long-term load within design load ○ ○ D2 Long-term load over design load ○ D3 Short-term load within design load ○ ○ D4 Short-term load over design load ○ D5 Insufficient cross section or quantity of steel ○ D6 Differential settlement of structure ○ D7 Freezing heave ○
Introduction of a Japan Concrete Institute Guideline: Practical Guideline for 221 Investigation, Repair and Strengthening of Cracked Concrete Structures
Standard investigation
Detailed investigation
Estimation of causes
Table 6
Evaluation method I (Section 4.2) Evaluation method II (Section 4.3) Evaluation method III (Section 4.4) Cracks which are considered to stop Cracks which are considered to be Cracks for which “Evaluation I” and proceeding in several years (drying progressive “Evaluation I” cannot be applied shrinkage cracks and so on) If no good If no good
Fig. 2 Proceedings of evaluation.
Table 7 Influence of crack on the performance of member from the viewpoints of steel corrosion. Environmental condition Chloride and corrosion Normal outdoor Indoor or underground w > 0.5 Large (20-year durability) Large (20-year durability) Large (20-year durability) 0.4 < w ≤ 0.5 Large (20-year durability) Large (20-year durability) Medium (20-year durability) Crack width: w 0.3 < w ≤ 0.4 Large (20-year durability) Medium (20-year durability) Small (20-year durability) (mm) 0.2 < w ≤ 0.3 Medium (20-year durability) Small (20-year durability) Small (20-year durability) w ≤ 0.2 Small (20-year durability) Small (20-year durability) Small (20-year durability) Small: crack does not cause the degradation of performance and the required performance is satisfied; Medium: although crack is the cause of performance degradation, slight repairs are effective; Large: the performance degradation is remarkable and the member has not satisfied the required performance. The value in the parentheses means the standard period that can guarantee the evaluation result of durability. “20-year durability” means that it is about 15~25 years to guarantee the result of evaluation after cracking. “20-year” is the average of 15 years and 25 years.
Table 8 Influence of crack on the performance of member from the viewpoints of water leakage. Environmental condition and Under water pressure Others member thickness (mm) Less than 180 More than 180 Less than 180 More than 180 w > 0.2 Large Large Large Large Crack width: 0.15 < w ≤ 0.20 Large Large Large Medium w (mm) 0.05 < w ≤ 0.15 Medium Medium Medium Small w ≤ 0.05 Small Small Small Small Small: crack does not cause the degradation of performance and the required performance is satisfied; medium: although crack is the cause of performance degradation, slight repairs are effective; large: the performance degradation is remarkable and the member does not satisfy the required performance.
4.4 Evaluation-III (Applied for Cracks Due to Evaluation-II. Combined Deterioration, etc.) 5. Judgment of Necessity of Repair and Evaluation-III should be carried out based on Strengthening advanced judgment by an expert engineer. 5.1 General Evaluation-III should be applied when the required performance is structural safety, durability or water In order to ensure the performance of cracked tightness for a long period. Evaluation-III can be also concrete structures, necessity of repair and applied to the crack due to combined deterioration or strengthening should be judged by owner of the the crack which cannot be evaluated by Evaluation-I or structures in view of influence of cracks on
222 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures performance of members or structures and specific same procedure to Evaluation-I can be adopted. limitation such as importance of structures. In the case that Evaluation-III is carried out, taking The necessity of repair and strengthening should be expected remaining service life into consideration, judged by the methods shown in Section 5.2 based on repair and strengthening should be performed by a the results of evaluation of cracks in view of expected professional engineer based on the results of evaluation remaining service life, social importance of structures of cracks. and economic efficiency. If results of the evaluation are 6. Repair and Strengthening not taken into consideration in the judgment of necessity of repair and strengthening, the repair and the 6.1 General strengthening for cracks do not connect with successful The method most suitable for the purpose of repair effect and the cost can become bigger. Thus, it is very or strengthening for cracks is to be adopted based on important to take results of the evaluation of cracks into investigation, evaluation and judgment on necessity of consideration in order to maximize the effect of the repair or strengthening. The certified personnel, in repair and the strengthening. principal, executes repair and strengthening.
5.2 Methods of Judgment 6.2 Design of Repair and Strengthening
In the case Evaluation-I which is carried out from 6.2.1 Basis of Repair and Strengthening Design the viewpoint of durability for steel corrosion, the Repair and strengthening design are carried out to judgment of necessity of repair can be performed based maintain the performance of the structure up to a on Table 9. certain level during the design service life of the In the case Evaluation-I which is carried out from structure expected by the owner when repair and the viewpoint of water resistance and water tightness, strengthening works are executed. at this moment, the judgment of necessity of repair can 6.2.2 Note of Repair and Strengthening Design be performed based on Table 10. The following points are to be considered during In the case, Evaluation-II is carried out, almost the repair and strengthening design:
Table 9 Table for judgment based on Evaluation Method I (in view of durability for steel corrosion).
Influence on performance Expected remaining service life of members Less than 10 years From 10 to 20 years Over 20 years Repair is unnecessary Small (20-year durability) Repair is unnecessary Repair is unnecessary (investigation of cracks should be done constantly) Repair is basically unnecessary Repair is basically unnecessary Medium (repair is necessary according to the (repair is necessary according to Repair is necessary (20-year durability) circumstances, and investigation of the circumstances) cracks should be done constantly) Repair is basically necessary Repair is necessary (including Large (20-year durability) (repair is unnecessary according Repair is necessary strengthening, demolishment to the circumstances) and removal)
Table 10 Table for judgment based on Evaluation Method I (Viewpoint of water resistance and water tightness). Influence on performance of members Judgment Small Repair is unnecessary Repair is basically unnecessary (repair is unnecessary according to the circumstances, Medium and investigation of cracks should be done constantly) Large Repair is necessary
Introduction of a Japan Concrete Institute Guideline: Practical Guideline for 223 Investigation, Repair and Strengthening of Cracked Concrete Structures
(1) An effective repair is done based on the plaster method; investigated causes of crack; mortar injection method; (2) The repair and strengthening method and the concrete filling method; material are selected considering the expected service spray method; life; (3) surface coating method: (3) Even when strengthening is made, it is necessary surface coating method (which is used not only to do an appropriate repair. for cracks, but also for the entire concrete surfaces); 6.2.3 Additional Survey for Repair Design (4) spalling prevention method: Additional survey for the repair design is carried out anchor pinning method; to make up for the lack of necessary information. fiber sheet covering method; 6.2.4 Selection of Repair Method renewal method for external wall by net over; The repair method of each structure should be (5) electrochemical repair method: selected based on major causes of crack, evaluation, cathodic protection method; judgment result, expected life period, and level of desalination method; recovery target. re-alkalization method; 6.2.5 Selection of Strengthening Method the electro deposition method. In the case of strengthening concrete structures 6.4 Strengthening Method whose structural strength is decreased due to the generation of crack, the appropriate method most In the case of strengthening concrete structures, the suitable for the purpose of strengthening is adopted method most suitable for the purpose of strengthening based on investigation, cause estimation, advance is to be adopted based on the appropriate prediction of degradation, and judgment on the understandings of the strengthening method and used necessity of strengthening. materials. In this case, the load carrying capacity of the The target load carrying capacity after strengthening member (or the structure), the conditions for the shall be determined taking into account the strengthening works, and the environmental conditions combination with repair methods and durability during should be considered. the expected service life by the owner. In this section, the strengthening methods are classified into five categories and their characteristics 6.3 Repair Method and important points are introduced. Suitable methods complying with the objectives The five categories of strengthening methods are as should be applied for repair with understanding the follows: cause of deterioration and damage and characteristics (1) member replacement: of methods themselves. The following categories of replacing method; repair methods are applied: (2) addition of concrete sections: (1) the crack repair methods: surface overlaying method; crack covering method (the method is used to concrete jacketing method; cover only the crack); (3) bonding and jacketing: injection method; steel plate bonding method; filling method (the method is used when the continuous fiber sheet bonding method; reinforcement is not corroded); steel plate jacketing method; (2) section repair method: continuous fiber sheet jacketing method;
224 Introduction of a Japan Concrete Institute Guideline: Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures
rebar addition method; (6) The contractors should make records of works (4) introduction of pre-stress: and completion. external cable method; 6.7 Inspections (5) addition of members: member addition method. (1) The owner should make the inspection plan with the consideration of the importance of the structure, the 6.5 Repair and Strengthening Materials expected remaining life and the cost/benefit, and the To select the repair and strengthening materials, it is owner should inspect the designs and works of repair necessary to choose the suitable material that complies and strengthening of the construction; with the repair and strengthening method. In choosing, (2) For the design inspection, the owner should the characteristics of the method and the materials check whether the design is appropriate to satisfy the should be understood. Also, the causes of the required performances of the members (structures) deterioration and damage should be understood. during the expected remaining life, based on the Repair and strengthening materials can be divided investigation, causes estimation and judgment; roughly into the following four types for which the (3) For the work inspection, the owner should check characteristics and important points are described in whether the repair and strengthening works are done as this guideline: designed; cementitious materials; (4) If the owner judged the design or the works are polymer materials; not satisfied, the designer or the contractor should metals; make appropriate measures. fibrous material; 6.8 Records and Interim Observations others. The recommended inspections are to be executed 6.6 Repair and Strengthening Works periodically after the repair and strengthening, and the Contractors should note the items below when records are to be saved. executing the repair and strengthening works: 7. Conclusions (1) The contractors should obey the related laws; (2) The contractors should complete work plans A guideline of JCI (Japan Concrete Institute): after carrying out necessary pre-investigation; Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures, is (3) The contractors should understand the characteristics of the materials and determine the briefly introduced. If you are interested in this ranges of temperature and humidity to ensure the guideline, reading of the original guideline is strongly required performances of the materials. Also, they recommended. Owners or managers of the concrete should determine reasonable work schedules; structures will correspond effectively if this guideline (4) The contractors should give necessary was used, maintenance management can be performed rationally and efficiently, thus and so, also related to explanations to the users of the structures and decrease of LCC (life cycle cost) in the near future. neighborhood publics (public involvement) before the work. Moreover, they should make and submit References necessary documents to the authorities; [1] JCI (Japan Concrete Institute). 2009. Practical Guideline (5) The contractors should control the construction for Investigation, Repair and Strengthening of Cracked works in every stages; Concrete Structures—2009. Japan: JCI.
Journal of Civil Engineering and Architecture 9 (2015) 225-231 doi: 10.17265/1934-7359/2015.02.011 D DAVID PUBLISHING
Trends and Causes of Traffic Accidents in Dubai
Akmal Abdelfatah1, Mohamed Saif Al-Zaffin2 and Waleed Hijazi1 1. Civil Engineering Department, American University of Sharjah, Sharjah 26666, United Arab Emirates 2. General Department of Traffic Police, Dubai Police, Dubai 1493, United Arab Emirates
Abstract: This paper investigates the traffic accidents’ trends and causes in Dubai. For this purpose, the traffic accident statistics for years 2003 to 2012 are used to examine the trends of different types of accidents and the causes of these accidents. Also, the paper determines the most common types of accidents over the study period and identifies some of the causes for these accidents. Furthermore, the paper shows the impact of the new traffic law amendments, which were issued in 2008, on the accident rates and trends. The results showed that the implementation of the traffic law amendments did not have major impact in year 2008. However, there was a significant effect of these amendments in the following years. Also, lack of awareness of traffic laws and regulations in Dubai has been proven to be one of the major causes of accidents. Finally, the paper provides some recommendations to reduce the traffic accident rates, in order to achieve the Dubai Police Department 2020 strategic goal to have zero fatalities.
Key words: Traffic safety, accident causes, fatalities.
1. Introduction accidents and fatalities as related to the population or the number of vehicles registered in a certain city or Dubai has witnessed a very high population and country. In 2004, the WHO (World Health economic growth rate over the past two decades. This Organization) [1] reported that traffic accidents are the increase was, unfortunately, accompanied by an 9th cause of death, with a total number of deaths equal increase in the traffic accident rates as well, which were to 1.3 million. Lately, WHO showed that road higher than the rates observed in most of the western accidents were the cause for 1.24 million fatalities countries. Having a similar situation in most of the worldwide. The data in the report were collected from major cities in the UAE (United Arab Emirates), the 182 countries around the world and included about government of UAE has recognized this increase and 99% of the world’s population [2]. This shows the applied major amendments of the Federal Traffic Law seriousness of the situation and the need for major as of March 2008. The new system implemented much efforts to improve the current systems which can result higher penalties on traffic offences and introduced in decreasing the number of fatalities due to road registration of traffic points even in absentia offenses accidents. unlike the previous system that registers traffic points Other research efforts studied the road traffic only for spot offenses. In addition to these amendments, accidents in China for the period 2000-2005. The Dubai Police Department has declared that the strategic research concluded that the driver experience, the goal for Dubai is to have zero fatality per hundred classification of the road, and the level of urban thousand of population by the year 2020. development surrounding the road are the main factors 2. Literature Review that characterize the accidents’ fatalities in China. In addition, there are other reasons that include: cultural There are several studies that deal with the rate of issues such as drunk driving, poor road performance that is due to limited funding, overloaded heavy trucks Corresponding author: Akmal Abdelfatah, Ph.D., associate professor, research fields: transportation engineering and traffic because of expensive toll, resulting in more sever analysis. E-mail: [email protected].
226 Trends and Causes of Traffic Accidents in Dubai fatalities and lack of safety. It suggested allocating flow. The results concluded that the consideration of fund for investments in transportation infrastructure homogeneous or nonhomogeneous traffic has a that is not only beneficial to traffic but also to the significant impact on the accidents’ trends [9]. A national GDP (gross domestic product). Furthermore, similar study used regression analysis to evaluate the the road traffic safety system in China needs to be traffic accident data in Jordan and the UAE from 1990 enhanced [3, 4]. Peng et al. [5] considered the traffic till 2004, and Qatar till 2006. The study results accidents in urban areas in China, where the population indicated that exponential models showed the best fit to growth is causing higher frequency of traffic accidents. predict the relationship between number of fatalities They utilized a database that includes historical data and the population or number of vehicles. The models regarding road traffic accidents in Shanghai. The data showed an acceptable average absolute error of 20.9% were studied in order to determine the relationship for Qatar, 10.9% for Jordan and 5.5% for the UAE. between traffic accidents and the road parameters. Also, the authors concluded that the gross domestic They also provided recommendations to the local income and the fatality rate showed a strong linear authorities in order to improve the traffic safety on relationship [10]. The effect of driver’s age on traffic local roads. Another research evaluated the characters accidents in Florida US has been studied by Abdel-Aty and causes of accidents migration in south China [6]. et al. [11]. The authors used the 1994 and 1995 traffic Another important reason for road traffic accidents accident data in Florida to develop log-linear and logit is related to the driver behaviour. The attitude of the models. These models considered the relationship drivers was examined through surveying 2,614 drivers between the driver’s age and several factors that impact in Norway. The questionnaire results indicated that traffic accidents, such as traffic volume, severity of the behaviours such as speeding and rule violations, injury, types of collision, road type, and speed careless driving, attitude towards drinking and driving distribution. are among the most important behaviours that impact As a way to decrease the number of accidents, the involvement in accidents. It was also concluded approach traffic calming processes have been studied that age and gender are significant factors that impact by Knapp [12]. The speed-control measures are the variations of drivers’ attitude [7]. controlled by three ways: vertical speed control, Erdogan [8] evaluated the situation in Turkey using horizontal speed control and narrowing. Vertical speed the accident data for 2001-2006 and concluded that control includes humps placed across the roadway. On although there is a decrease in fatalities, the fatalities the other hand, the horizontal speed control is placed on ratio is still high when compared to developed the road to force the driver to change direction in order countries. There are many improvements that could be to pass it. The narrowing includes the curb extension applied to the transportation system in terms of safety that reduces space in which a car can pass through. to decrease fatalities. In conclusion, it is clear that the traffic accidents are As a result of a study on the rural Sweden roads, it causing major problems in different parts of the world. was mentioned that the presented data should consider Many of the reasons for accidents that have been many factors such as environmental issues, and the reported in the literature are applicable to Dubai, such type of the traffic flow, for instance, to be as speeding, rule violations, and careless driving. homogeneous (light vehicles only) or However, some of the most common reasons for nonhomogeneous (light and heavy vehicles). The study accidents in China and Europe are not very common in developed empirical models describing the Dubai, such as drunk driving. As for the road relationships between accident frequency and traffic conditions, it is not a major problem in Dubai as most
Trends and Causes of Traffic Accidents in Dubai 227 of the roads are fairly new and have been designed and population and the other is based on number of constructed according to the international standards. registered vehicles. Based on the regression analyses, the research recommends more reliable rate to be used 3. Data Collection for accident analysis in Dubai. Furthermore, the The data collected in this paper are from different research defines the most common types of accidents in sources. The number of accidents and population from Dubai and determines the general trend of these 2003 till 2012, and the number of registered vehicles common types of accidents based on regression from 2003 till 2005 are provided by the General analysis. Department of Traffic Police, Dubai Police. The 5. Analysis and Discussion number of registered vehicles in Dubai from 2006 till 2012 is obtained from RTA (Road and Transportation Table 1 shows the total number of accidents, Authority). population, rate of accidents per 100,000 population, the number of registered vehicles, and the rate of 4. Research Methodology accidents per 10,000 registered vehicles for years 2003 The research is aiming at using regression analyses to 2012. to estimate the trend of accidents in Dubai. Two Fig. 1 shows the data for the number of accidents per accident rates will be analysed: one based on 100,000 population and the regression analysis results
Table 1 Traffic accident data of Dubai (2003-2012). Accidents per 100,000 Number of registered Accidents per 10,000 Year Total number of accidents Population population vehicles registered vehicles 2003 2,287 1,141,487 200.4 435,722 52.5 2004 2,413 1,228,178 196.5 500,272 48.2 2005 2,794 1,321,453 211.4 630,000 44.3 2006 3,224 1,421,812 226.8 740,187 43.6 2007 3,335 1,529,792 218.0 868,592 38.4 2008 4,011 1,645,973 243.7 996,997 40.2 2009 3,576 1,770,978 201.9 1,021,880 35.0 2010 2,686 3,300,000 81.4 1,031,961 26.0 2011 2,636 3,361,183 78.4 1,055,412 25.0 2012 2,932 4,089,107 71.7 1,137,750 25.8
300.0 243.7 226.8 250.0 211.4 218.0 200.4 196.5 201.9 200.0 Accidents per 100,000 Pop 150.0 population 81.4 78.4 71.7 100.0 Polynomial多项式 (Accidents (accidents per per100,000 y = -4.710x2 + 35.55x + 158.8 50.0 R² = 0.815 100,000Pop) population) 0.0
Accidents per 100,000 population population per 100,000 Accidents 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year
Fig. 1 Accidents per 100,000 population in Dubai (2003-2012).
228 Trends and Causes of Traffic Accidents in Dubai
for the trend of accidents. The most suitable regression km/h above the speed limit), running away from a is a polynomial curve (second order) with a coefficient policeman, and falling or leaking load for trucks). of determination (R2) value of about 0.82. The Consequently, the number of accidents is in decrease. regression analysis shows a good fit with the actual It seems that the use of the rate of accidents per data. 100,000 of the population might not be as good as the Fig. 2 illustrates the rate of accidents per 10,000 rate of accidents per 10,000 registered vehicles. This registered vehicles in Dubai and the regression analysis fact can be attributed to the fact that there is a large results. It is clear that the linear regression for this case segment of the population in Dubai who are presents an excellent fit with an R2 of about 95%. construction workers that do not travel a lot. This Considering the results shown in Figs. 1 and 2, it can conclusion is drawn based on the regression analyses be noticed that there is a general decreasing trend in the results. According to the equation shown in Fig. 1, the total number of accidents. As in Figs. 1 and 2, there is a number of accidents per 100,000 population can reach significant reduction in the number of accidents 0 in year 2013, which is not realistic. However, the between 2008 and 2009. This can be attributed to the equation shown in Fig. 2 shows that the number of application of the new traffic law that applied the accidents is expected to be 0 (or practically a very traffic points’ system. This system was announced in small value) between 2019 and 2020, which is more March 2008 and it authorizes police departments in acceptable. UAE to withdraw a driving license when the drivers are Accidents in Dubai are classified into six categories involved in serious traffic violations. According to the as illustrated in Table 2. The accident categories are: (1) new system, a driving license is withdrawn if the driver hitting a stationary object; (2) hitting a person; (3) flip receives a total of 24 traffic points with a 12-month over; (4) hitting an animal; (5) falling; (6) hitting a period. Some violations are penalized by 24 traffic moving object (include accidents between two cars). points (such as drunk driving, driving a vehicle without Headings of Table 2 are given numbers that refer to a license plate, not stopping after causing an accident previous sequence. with injuries, and dangerous overtaking by trucks). As shown in Table 2, the most common type of Also, some other violations are considered serious as accidents is hitting a moving object that includes they result in a penalty of 12 points (such as dangerous accidents between cars (Type 6). This represents more driving “racing”, reckless driving, speeding (driving 60 than 60% of the total accidents from 2003 till 2012, as
60.0 52.5 48.2 50.0 44.3 43.6 38.4 40.2 Accidents per 10,000 Vehicle 35.0 Accidents per 10,000 vehicles 40.0 registeredRegistered y = -3.143x + 55.19 26.0 25.0 25.8 Linear (accidents per 10,000 30.0 R² = 0.945 线性 (Accidents per 10,000 vehicleVehicle registered) Registered) 20.0 10.0 0.0 Accidents per 10,000 vehicle registered registered vehicle 10,000 per Accidents 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year
Fig. 2 Death per 10,000 registered vehicles in Dubai (2003-2012).
Trends and Causes of Traffic Accidents in Dubai 229
Table 2 Types of accidents in Dubai (2003-2012). % of % of % of % of % of % of Year Type 1 Type 2 Type 3 Type 4 Type 5 Type 6 Type 1 Type 2 Type 3 Type 4 Type 5 Type 6 2003 312 13.6 408 17.8 200 8.8 19 0.8 5 0.2 1,343 58.7 2004 298 12.4 479 19.9 141 5.8 11 0.5 9 0.4 1,475 61.1 2005 437 15.6 505 18.1 135 4.8 15 0.5 13 0.5 1,689 60.5 2006 486 15.1 603 18.7 129 4.0 7 0.2 8 0.3 1,991 61.8 2007 456 13.7 665 19.9 130 3.9 10 0.3 10 0.3 2,064 61.9 2008 545 13.6 754 18.8 176 4.4 9 0.2 16 0.4 2,511 62.6 2009 493 13.8 537 15.0 177 5.0 8 0.2 11 0.3 2,350 65.7 2010 439 16.3 336 12.5 143 5.3 10 0.4 12 0.5 1,746 65.0 2011 418 15.9 333 12.6 138 5.2 2 0.1 8 0.3 1,737 65.9 2012 511 17.4 359 12.2 146 5.0 5 0.2 6 0.2 1,905 65.0 Type 1: hitting a stationary object; Type 2: hitting a person; Type 3: flip over; Type 4: hitting an animal; Type 5: falling; Type 6: hitting a moving object (include accidents between two cars).
68.0 66.0 64.0 62.0 60.0 y = 0.757x + 58.64 58.0 % of accidentAccident Type Type 6 6 56.0 R² = 0.867 Linear (% of accident Type 6) 54.0 线性 (% of Accident Type 6)
Percentage of accident Type 2 2 Type accident of Percentage 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year
Fig. 3 Percentage of accidents due to hitting a moving object (2003-2012). indicated in Fig. 3. The regression analysis for this type conducted several awareness campaigns that targeted of accidents shows a very good fit with an R2 of about all types of road users including pedestrians has a 0.87. Also, the trend is increasing, which indicates that significant contribution to the reduction in this type of the percentage for this type of accidents is increasing accidents. over years. The driving behaviour is the main cause of Finally, the third most common type of accidents is such accidents. accident Type 1 (hitting a stationary object), which The second most common accident is hitting a represents about 15% of the total number of accidents person (Type 2) with a percentage of almost 17% of the in Dubai. The trend for Type 1 accidents is depicted in total accidents, shown in Fig. 4. The regression Fig. 5. The regression analysis for this type did not analysis for this type of accidents resulted in a show a strong fit as the R2 is about 0.54. However, the polynomial equation (second order) with an R2 of about trend shows a slight increase in the percentage of these 0.82. The trend of this type of accidents is decreasing. accidents. This type of accident is hitting a stationary This can be attributed to the fact that the authorities in object, which is caused by the bad drivers’ behaviour. Dubai are implementing more physical restrictions to These three most common types of accidents in control the location of pedestrian crossings. Also, the Dubai represent about 95% of the total number of fact that Dubai Traffic Police Department has accidents. In addition to that, the two types of accidents
230 Trends and Causes of Traffic Accidents in Dubai
25.0 20.0 15.0 2 % of accidentAccident Type Type 2 2 10.0 y = -0.156x + 0.865x + 17.81 R² = 0.824 Polynomial多项式 (% (%of Accidentof accident Type Type 2) 2) 5.0 0.0
Percentage of accident Type 2 2 Type accident of Percentage 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year
Fig. 4 Percentage of accidents due to hitting a person (2003-2012).
20.0 15.0 %% of accidentAccident Type Type 1 1
10.0 y = 0.057x2 − 0.281x + 14.06 Polynomial多项式 (% (% of of Accident accident Type 1) 5.0 R² = 0.541 1) 0.0
Percentage of accident Type 1 1 Type accident of Percentage 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year
Fig. 5 Percentage of accidents due to hitting a stationary object (2003-2012). that depend on the drivers’ behaviour (Types 6 and 1) of drivers involved in the accidents; represent more than 80% of the total number of considering the number of traffic fines issued and accidents in Dubai. This is an alarming sign that the examining its impact on the traffic safety. Dubai Traffic Police Department has to consider when 7. Conclusions applying new strategies to improve the traffic safety on Dubai’s roads. In contradiction to the trend of the Type The number of accidents is of a major concern to 6 accidents, Type 2 accidents show a reducing trend. Dubai Government in general and to the Dubai Traffic Police Department in specific. The paper showed the 6. Future Work trends of the total number of accidents and the most The authors are planning for some future work to common types of accidents in Dubai. The total number expand this research. Some of the proposed future of accidents has an increasing trend from 2003 to 2008, studies are: followed by a decreasing trend from 2009 till 2012, considering the rate of fatalities as an indicator of which is mainly due to the implementation of a new traffic safety on Dubai roads; traffic law in Dubai. The reduction in accident rates as investigating the distribution of the characteristics related to population and number of registered vehicles
Trends and Causes of Traffic Accidents in Dubai 231 is a positive sign of an improved safety on Dubai roads. [2] WHO. 2013. Global Status Report on Road Safety 2013. WHO. However, the rate of accidents per 10,000 registered [3] Zhao, S. 2007. “Rapid Motorization and Road Traffic vehicles is a more robust measure. Accidents in China.” In Proceedings of the 11th World Furthermore, data show that there are different types Conference on Transportation Research [CD-ROM]. of accidents where the most common one is hitting a [4] Zhao, S. 2009. “Road Traffic Accidents in China.” International Association of Traffic and Safety Sciences 33 moving object and then hitting a person followed by (2): 125-7. hitting a stationary object. The first and third common [5] Peng, C., Lu, J., and Yin, W. 2010. “An Empirical Study types mainly depend on driving skills, while the second of the Urban Traffic Accident Causes with type is influenced by both the driving skills and the Correspondence Analysis Method.” In Proceedings of the 10th International Conference of Chinese Transportation awareness of the public. Therefore, Dubai authorities Professionals, 1299-306. (RTA and Dubai Police Department) may consider [6] Jiao, C., Yang, M., and Hao, Y. 2009. “Analysis of some of the following recommendations to improve Characters and Causes of Road Traffic Accident Migration.” the traffic safety and help in reducing the accident rates In Proceedings of the 9th International Conference of Chinese Transportation Professionals, 662-8. further: [7] Iversen, H., and Rundmo, T. 2004. “Attitudes towards apply stricter driving tests when issuing a new Traffic Safety, Driving Behaviour and Accident driving license. Also, whenever a driving license is Involvement among the Norwegian Public.” Ergonomics withdrawn because of traffic violations, the driver has 47 (5): 555-72. [8] Erdogan, S. 2009. “Explorative Spatial Analysis of Traffic to go through a stricter training program. In addition to Accident Statistics and Road Mortality among the that, keeping track of the violations’ records of these Provinces of Turkey.” Journal of Safety Research 40 (5): drivers in the future and applying tougher penalties on 341-51. them might help in reducing the number of accidents; [9] Hiselius, L. 2004. “Estimating the Relationship between Accident Frequency and Homogeneous and continue to conduct traffic awareness campaigns Inhomogeneous Traffic Flows.” Accident Analysis and using different languages as the population in Dubai Prevention 36 (6): 985-92. includes significant groups from different parts of the [10] Bener, A., Hussain, S. J., Al-Malki, M. A., Shotar, M. M., world; Al-Said, M. F., and Jadaan, K. S. 2010. “Road Traffic Fatalities in Qatar, Jordan and the UAE: Estimates Using consider higher penalties for causing accidents, Regression Analysis and the Relationship with Economic especially the accidents that are caused by the personal Growth.” East Mediterranean Health Journal 16 (3): errors of the driver or pedestrian. 318-23. These suggestions may result in some improvements [11] Abdel-Aty, M., Chen, C., and Schott, J. 1998. “An Assessment of the Effect of Driver Age on Traffic in the accidents’ trends in Dubai. Accident Involvement Using Log-Linear Models.” Accident Analysis and Prevention 30 (6): 851-61. References [12] Knapp, K. 2000. “Traffic-Calming Basics.” Civil [1] WHO. 2004. The Global Burden of Disease. Switzerland: Engineering—ASCE (American Society of Civil WHO. Engineers) 70 (1): 46-9.
Journal of Civil Engineering and Architecture 9 (2015) 232-243 doi: 10.17265/1934-7359/2015.02.012 D DAVID PUBLISHING
Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation
Fotis S. Mertzanis1, Antonis Boutsakis1, Ikaros-Georgios Kaparakis1, Stergios Mavromatis2 and Basil Psarianos3 1. School of Civil Engineering, National Technical University of Athens, Athens 15452, Greece 2. School of Civil Engineering and Surveying and Geoinformatics Engineering, Technological Educational Institute of Athens, Athens 12210, Greece 3. School of Rural and Surveying Engineering, National Technical University of Athens, Athens 15452, Greece
Abstract: The adopted 2-D SSD (stopping sight distance) adequacy investigation in current design practice may lead to design deficiencies due to inaccurate calculation of the available sight distance. Although this concern has been identified by many research studies in the past, none of them suggested a comprehensive methodology to simulate from a 3-D perspective concurrently both the cross-section design and the vehicle dynamics in space during emergency braking conditions. The proposed methodology can accurately perform SSD adequacy investigation in any 3-D road environment where the ground, road and roadside elements are inserted by identifying areas of interrupted vision lines between driver and obstacle being less than the required distance necessary to bring the vehicle to a stop condition. The present approach provides flexibility among every road design and/or vehicle dynamic parameter inserted, as well as direct overview regarding design elements that restrict the driver’s vision and create SSD inadequacies. As a result, precious guidance is provided to the designer for further alignment improvement but mostly an accurate aid to implement geometric design control criteria with respect to both existing as well as new road sections is delivered. The efficiency of the suggested methodology is demonstrated through a case study.
Key words: SSD, 3-D road alignment, design consistency, road safety.
1. Introduction In current practice, some efforts have been made recently to overcome this incorrect SSD determination In existing road design policies [1-4], despite the by establishing some coordination between the fact that 3-D perspective is essential in order to horizontal and vertical curve positioning, although not evaluate the final outcome, the adoption of critical all the design cases are addressed. For example, the design parameters is restricted on a fragmented 2-D Green Book [1] stresses that in order to grant the SSD road environment. Such a typical case of design provision, the vertical transition curve should be misconception is performed while determining the entirely designed inside the horizontal curve. In the critical parameter of SSD (stopping sight distance). relevant Spanish Design Guidelines [3], the desired The 2-D SSD calculation is inaccurate. The impact horizontal-vertical arrangement is reached when the of this approach can be detrimental to the cost and/or vertical crest curve falls completely inside the design consistency of existing and new road facilities, horizontal curve including spirals. in terms of adopting excessive overdesign suggestions The present paper introduces an analytical method (e.g., increase of the inner shoulder width of divided for 3-D sight distance analysis that considers the 3-D highways) or unnecessary posted speed areas, where, configuration of the roadway as well as the dynamics in each case, safety violations might occur as well. of a vehicle moving along the actual 3-D roadway path, based on the difference between the available and the Corresponding author: Fotis S. Mertzanis, Ph.D. candidate, research field: transportation engineering. E-mail: demanded SSD. [email protected]. Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation 233
The suggested SSD adequacy investigation is between the driver’s eye and an object, against all the incorporated in “H12” (2012) road design software, possible sight obstructions, by using an iterative developed at the NTUA (National Technical procedure. University of Athens) for academic purposes [5], Lovell et al. [9] developed a method to calculate the where many consultant firms in Greece use it as well. sight distance based on horizontal geometry, without The efficiency of the suggested methodology is considering the effect of vertical geometry. Nehate and demonstrated through a case study. Rys [10] described a methodology to define the available sight distance using GPS (global positioning 2. SSD Modeling system) data by examining the intersection of line of The SSD adequacy analysis is based on either 2-D or sight with the elements representing the road surface. 3-D models. The 2-D SSD investigation is rather However, the available sight distance was not based on fragmentary and may produce design deficiencies due the road’s compound (horizontal and vertical) to inaccurate calculation of the available sight distance, alignment. where even more critical situations might occur. In the past years, in order to evaluate the actual sight Hassan et al. [6], for example, stated that 2-D SSD distance in real driving conditions, a number of 3-D investigation may underestimate or overestimate the models are found in the literatures [11-17] which were available sight distance and consequently lead to safety based on their performance through the correlation violation. between the road surface, the ground terrain and the This concern has been identified by many roadside environment aiming to optimize the available researchers in the past and a wide range of 2-D and 3-D sight distance. approaches have been developed to address the Recently, Kim and Lovell [18] delivered a 3-D sight problem. One of the first researchers that assessed the distance evaluation method where an algorithm is used available sight distance on 3-D alignment, Sanchez [7] to determine the maximum available sight distance studied the interaction between the sight distance and using computational geometry and thin plate spline the 3-D combined alignment idealized into a net of interpolation to represent the surface of the road. The triangles using inroads software. In this research, the available sight distance is measured by finding the operator, assisted by the different views generated by shortest line that does not intersect any obstacle. the computer, was able to determine the obstruction Jha et al. [19] proposed a similar to the present paper impeding the driver’s sight line. Although this 3-D methodology for measuring sight distance along a methodology was accurate, it was very time consuming roadway’s centerline, utilizing triangulation methods since the available sight distance was determined via an introduced for this purpose algorithm, consisting graphically (not analytically). of three stages, namely, road surface development, Several years later, Hassan et al. [8] presented an virtual field of view surface development, and virtual analytical model for computing available sight distance line of sight plane development. However, the process on combined horizontal and vertical highway involved multiple software platforms, thus delivering alignments, using parametric finite elements (four, six an accurate but non-flexible outcome. and eight-node rectangular elements as well as The abovementioned 3-D models are capable of three-node triangular elements) to represent the accurately simulating compound road environments highway and sight obstructions. The idea behind the where an unsuccessful arrangement of vertical and proposed model is summarized in checking the driver’s horizontal alignment may exist, and thus allows the sight line, which is represented by a straight line definition of the actual vision field to the driver.
234 Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation
However, as already stated above, most of the environment (Visual Basic). This “sub-software” is previously mentioned research studies are focused on part of H12 (2012) road design software [5] and the optimizing the available SSD by introducing either flowchart is shown in Fig. 1. H12 software consists of new algorithms or design parameter combinations, various individual sub-routines through which certain ignoring, in many cases, the topographic visual road design stages are processed, namely, the creation restraints. Moreover, none of the abovementioned of terrain model, horizontal alignment, vertical approaches suggested a comprehensive methodology alignment, cross-sections, Bruckner diagram and 3-D to simulate from a 3-D perspective concurrently both road model. Each sub-routine runs data entered by the the cross-section design and the vehicle dynamics in user and delivers data outputs, accessible by notepad as space during emergency braking conditions. well, and drawing outputs (in .dxf format). Furthermore, design elements responsible for SSD The design of the road’s typical cross-section, for inadequacies are accurately delivered, thus providing example, is formed by the following distinctive parts: precious guidance to the designer for further alignment main cross-section, road formations, cut-fill slopes, improvement. and ground formations until the ground is reached (Fig. 2). 3. Methodology The SSD adequacy investigation in this paper is As to investigate concurrently vehicles dynamics based on a recently developed methodology by the and 3-D road perspective impacts in SSD evaluation, a authors’ process that relates the 3-D configuration of a “sub-software” has been developed at NTUA by the roadway to the dynamics of a vehicle moving along the leading co-author [20] based on Microsoft’s Excel actual roadway path, based on the difference between
D.T.M. AUTOCAD FINALΤΕΛΙΚΗ CR- PARAMETERSΠΑΡΑΜΕΤΡΟΙ ΣΗΜΕΙΑ Μ.Ε. ΕΝΕΡΓΟACTIVE POINTS 2007 ΔΙΑΤΟΜΗSECTION LEGEND
ΜΟΝΤΕΛΟ ΚΟΡΥΦ ΕΣ AUTOCAD LONG.ALIGN.ΣΤΟΙΧΕΙΑ AUTOCAD ΥΨΟΜΕΤΡΑ ΣΗΜΕΙΑPOINTS D.T.M. VERTICES CUT/FILLΠΡΑΝΗ LEVELLING ΔΕΔΟΜΕΝΑDATA ΕΔΑΦ ΟΥΣ ΤΡΙΓΩΝΩΝ Μ.Ε. EPIK ΜΗΚΟΤΟΜΗΣDATA MKDM ΠΡΟΒΟΛΩΝ/ΧΘ ΟΡΙΖΟΝΤΙΟΓΡHOR.ALIGN. . WITHΜΕ CUT/FILLΠΡΑΝΗ ΑΡΧΕΙΑ ΤΕΧΝ. REPORT AUTOCAD ΠΛΕΥΡΕΣ ΔΙΑΤΟΜΕΣCROSS- AUTOCAD CR-SECTIONΕΠΙΚΛΙΣΕΙΣ AUTOCAD SLOPES/ΚΛΙΣΕΙΣ/ ΧΘCH,, Χ, Υ, Ζ ΕΚΘΕΣΗΣ SIDES DTM ΤΡΙΓΩΝΩΝ Μ.Ε. ΕΔΑΦSECTION ΟΥΣ MHKO ΔΙΑΤΟΜΩΝSLOPES DMRF FORMSΔΜΡΦ CR.-SECTIONΔΙΑΤΟΜΩΝ AUTOCAD ORPR AUTOCAD
ΜΗΚΟΤΟΜΗ AUTOCAD ΥΨΟΜΕΤΡΑ AUTOCAD CUMULATIVEΠΟΣΟΤΗΤΕΣ HYPSOMETRYΥΨΟΜΕΤΡΙΑ PROFILE AXLE ΕΔΑΦ ΟΥΣ MEO ΑΞΟΝΑ BRUC ΑΘΡΟΙΣΤΙΚΑQUANTITIES WORKINGΑΡΧΕΙΑ ΕΡΓΑΣΙΑΣFILES
HOR.POINT OF HOR.ΣΤΟΙΧΕΙΑ ALIGN. AUTOCAD ΕΛΕΓΧΟΙOMOE AUTOCAD QUANTITIESΠΟΣΟΤΗΤΕΣ - ΚΟΡΥΦ ΕΣ ΟΡΙΖΟΝΤΕΣHORIZONS ΜΕΟ INTERSECTION ΟΡΙΖΟΝΤΙΟΓΡDATA . YPSO CHECKSΟΜΟΕ XOMA M2 ΠΡΟΓΡΑΜΜΑPROGRAM
ΛΕΙΤΟΥΡΓΙΕΣUTILITIES CROSS- QUANTITIESΠΟΣΟΤΗΤΕΣ - WIDTHSΠΛΑΤΗ ΧΑΡΑΚΤΗΡCARDINALS. ΣΗΜΑΙΕΣFLAGS ΔΙΑΤΟΜΕΣ SECTIONS M3 ΚΑΤΗΓΟΡΙΕΣGROUND ΕΔΑΦQUALITY ΟΥΣ ΚΑΘΕΤΕΣ ΜΕΤΑΦΟΡΕΣ ΕΠΙΚΛΙΣΕΙΣSLOPES VERTICALS EARTH MOVE ΔΙΑΤΟΜΩΝ ΓΑΙΩΝ SLOPES/ΚΛ/ΔΜΡΦ FORMS AUTOCAD 3-DIMENSIONS3-ΔΙΑΣΤΑΣΕΙΣ ΑΡΙΣΤLeft RightΔΕΞ DIM3 HORIZONTAL ΧΘCROSS-, Χ, Υ PROJECTIONSΠΡΟΒΟΛΕΣ ΟΡΙΖΟΝΤ/ΦΙΑ ALIGNMENT ΔΙΑΤΟΜΩΝSECTIONS AUTOCAD ΓΕΩΜΕΤΡΙΑFORM ΤΑΧΥΤΗΤΕΣSPEED GEOMETRYΔΜΡΦ ΤΑΧΥ AUTOCAD ΧΘ , Χ , Υ CHAINAGESΧΘ AXLE ORIZ ΑΞΟΝΑ AUTOCAD ΙΔΙΟΤΗΤΕΣFORM ΟΡΑΤΟΤΗΤΕΣVISIBILITY PROPERTIESΔΜΡΦ ORAT ΜΕΓΑΛΑMAJOR PROJECTIONSΠΡΟΒΟΛΕΣ / STRUCTURESΤΕΧΝΙΚΑ /CHAINAGESΧΘ
CR-SECTIONΙΔΙΟΤΗΤΕΣ PROPERTIESΔΙΑΤΟΜΩΝ ΜΙΚΡΑMINOR ROADLINESΟ/Γ STRUCTURESΤΕΧΝΙΚΑ ΑριστLeft . ΔεξιέςRight
Fig. 1 H12 road design software interface.
Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation 235
Fig. 2 Distinctive parts of a typical cross-section (divided or undivided roadway can be outlined (divided case shown): 1. main cross-section; 2. road formations; 3. cut-fillslopes; 4. ground formations; 5. ground).
the provided and the demanded SSD. Both SSDdemanded incorporate the effect of these parameters, simple and SSDavailable are briefly presented below. considerations based on the mass point model as well as the laws of mechanics were applied respectively. 3.1 SSD Demanded Calculation Assuming the well-known Krempel’s [21] friction According to existing design policies, the demanded circle, the actual longitudinal friction provided for SSD consists of two distance components: the distance braking on curved sections is expressed by Eq. (2): traveled during driver’s perception-reaction time to the 2 2 Va 2 instant, the brakes are applied and the distance while (2) fT e braking to stop the vehicle. For example, the SSD gg R model adopted by many design policies is represented where: by Eq. (1): fT: friction demand in the longitudinal direction of travel; V 2 tVSSD 0 (1) V (m/s): vehicle (design) speed; 0 a g2 s a (m/s2): vehicle deceleration rate (e.g., 3.4 m/s2 [1] g and 3.7 m/s2 [2]); where: g (m/s2): gravitational constant;
V0 (m/s): vehicle initial speed; R (m): horizontal radius; t (s): driver’s perception-reaction time (e.g., 2.5 s [1] e (%/100): road cross-slope. and 2.0 s [2]); Aiming to quantify the grade effect during the g (m/s2): gravitational constant; braking process, the laws of mechanics through Eqs. (3) a (m/s2): vehicle deceleration rate (e.g., 3.4 m/s2 [1] and (4) were applied, assuming time fragments (steps) and 3.7 m/s2 [2]); of 0.01 s, in order to determine both the instantaneous s (%/100): road grade (upgrades (+), downgrades vehicle speed and pure braking distance: (-)). g tsfVV (3) However, the above approach ignores curved areas 1 Tii of both horizontal and vertical alignment, since, on one 1 g tsftVBD 2 (4) hand, the portion of friction provided in the ii 2 T longitudinal direction, assigned to serve the braking where: process, is associated directly to the friction demanded Vi (m/s): vehicle speed at a specific station i; laterally [21], and on the other hand, the grade values Vi + 1 (m/s): vehicle speed reduced by the deceleration involved in vertical curves are variable. In order to rate for t = 0.01 s;
236 Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation
t (s): time fragment (t = 0.01 s); In this paper, in order to laterally position the s (%/100): road grade in i position ((+) upgrades, (-) driver’s eyes at any desired offset from the typical downgrades); cross-section centerline, as well as to identify visibility
fT: friction demand in the longitudinal direction of levels due to the presence of these elements, the term travel; “roadlines” is introduced.
BDi (m): pure braking distance; Roadlines are defined as lines running longitudinally g (m/s2): gravitational constant. across the roadway that splits the road into areas of By applying Eqs. (3) and (4) subsequently, there is a uniform or linearly varied transverse slope. Fig. 3 sequence value i = k − 1 where Vk becomes equal to 0. shows, in cross-sectional view, an example of the
The corresponding value of ∑BDk – 1 represents the required roadlines in order to perform an SSD total vehicle pure braking distance for the initial value adequacy examination on the passing lane of a divided of vehicle speed. The demanded SSD is produced by road section. In the same figure, it can be seen that six adding the final pure braking distance to the distance roadlines should be defined per direction of travel, travelled during the driver’s perception-reaction time where besides the centerline: (first component of Eq. (1)) as follows: four roadlines define the Jersey barrier layout
SSDdemanded = V0t + ∑BDk – 1 (5) (points 1-4); where: one roadline defines the driver’s eye at an axis
V0 (m/s): vehicle initial speed; offset equal to half of the passing lane width (point 5); t (s): driver’s perception-reaction time (e.g., 2.5 s [1] one roadline (point 6) describes the roadway edge and 2.0 s [2]); line.
∑BDk – 1 (m): total vehicle pure braking distance for The roadline calculation step is user-specified and the initial value of vehicle speed. delivers a number n of cross-sections where n is Summarizing the demanded SSD determination, defined as the total roadway length divided by the Eq. (1) is used, enriched by the longitudinal friction selected calculation step. In general, a step value of 5 m and actual grade value portions, respectively, the effect delivers adequate precision. of which seems to be significant in combined The coordination of the roadlines is performed on horizontal and crest vertical curved alignments [22]. every cross-section from the very first to n, based on a relative coordinate system coinciding on the roadway’s 3.2 SSDavailable Calculation centerline and formed by the horizontal (x) and vertical The available sight distance depends mainly on the (y) distance of the roadline point (Fig. 3), which is alignment configuration. On horizontal tangents, the subsequently transformed to the absolute roadway road user feels comfortable regarding the length of coordinate system. visible roadway ahead, while on curved sections, the Furthermore, by connecting a point on one roadline driver’s available sight distance is reduced. However, with two relative points on an adjacent roadline, a the interaction between horizontal and vertical network of triangles is created representing the configuration on compound alignments imposes roadway surface. Similar is the process for the additional sight restrictions, furthermore assisted by formation of relevant triangles regarding the rest various cross-sectional elements, such as the presence distinctive parts of a typical cross-section shown in of Jersey barriers (on divided highways), metal steel Fig. 2. Between adjacent cross-sections where abrupt guardrails, or retaining walls, where even more critical roadline variations occur, an extra cross-section is safety situations may rise. interpolated. For example, in areas of road formation
Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation 237
Fig. 3 Roadline layout for SSD adequacy examination on the passing lane of a divided road section (the (-) sign refers to the left roadway; w: width; CL:CL center line). transitions between cuts and fills, the extra three-dimensional line, which can be defined by two station is calculated based on the adjacent cut and fill known points in space. In this case, these two points are heights. the driver’s eye and obstacle, let points be E(xE, yE, zE)
The creation of the final roadway model is based on and O(xO, yO, zO), respectively. In parametric form, the the triangulation of the above mentioned distinctive line’s equation is: parts. Finally, the road model is superimposed on the , 0,1 (11) ground model (initially triangulated) and the two where: models are merged with the prevailing road model. : a point on the line; The previously formed triangles are parts of : line’s initial point ( 0); different planes in space, the equations of which can be : direction vector, defined as: specified. A plane is defined by three non-linear points , , . in space (which, in this case, are the vertices of the By substituting the above in Eq. (11), the following triangle), let points be A(xA, yA, zA), B(xB, yB, zB) and parametric equations are derived:
C(xC, yC, zC), and the coordinates of which are known x = xE + (xO − xE)t from the triangulation above. Assuming a plane y = yE + (yO − yE)t (12) equation: z = zE + (zO − zE)t ax + by + cz + d = 0 (6) where, x, y, z: coordinates of a point along the line for a where, a, b, c and d are defined as: value of the parameter t.
a = yA(zB − zC) + yB(zC − zA) + yC(zA − zB) (7) Furthermore, the point corresponding to the line and
b = zA(xB − xC) + zB(xC − xA) + zC(xA − xB) (8) plane intersection, let point be M(xM, yM, zM) as shown
c = xA(yB − yC) + xB(yC − yA) + xC(yA − yB) (9) in Fig. 4a, is defined by substituting the line’s
d = -xA(yBzC − yCzB) – equations in the plane equation and solving for t. In this
xB(yCzA − yAzC) – xC(yAzB − yBzA) (10) case, the value of the parameter corresponding to the
The driver’s line of sight is, on the other hand, a point of intersection (tM) is defined as:
238 Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation
the point lies outside the triangle; dczbyax t OOO (13) If k, m < 0 and l > 0, then: if (y − y )(y − y ) M zzcyybxxa M AB M AC EO EO EO < 0, then the point lies inside the triangle, otherwise, Finally, applying Eqs. (12)-(15), the coordinates of the point lies outside the triangle. the intersection point are defined: 3.3 SSD Adequacy xM = xE + (xO − xE)tM (14)
yM = yE + (yO − yE)tM (15) SSD adequacy is granted when:
zM = zE + (zO − zE)tM (16) SSDdemanded ≤ SSDavailable (20) In order to specify whether point M lies inside the The available and demanded SSD values are defined triangle area, the following process is utilized: a through the difference of the road stations between random line on the x-y projection of the triangle starting and ending points, assumed at any desired axis passing through the projection of point M is offset and equal to the distance between the road’s constructed. Let AB, BC and AC be the points of centerline and, usually, half of the examined lane width. intersection of this line with the corresponding sides (or The above process, illustrated in the flowchart of Fig. 5, their extensions) of the triangle (Fig. 4b). The is incorporated in H12 road design software. following quantities are computed: In other words, the applied methodology is based on
k = (yAB − yA)(yAB − yB) (17) identifying areas of interrupted vision lines between
l = (yBC − yB)(yBC − yC) (18) driver and obstacle being less than the required
m = (yAC − yA)(yAC − yC) (19) distance necessary to bring the vehicle to a halt. The where, yAB, yBC and yAC are the ordinates of points AB, precision of the available SSD definition is a function BC and AC, respectively. of the selected incremental distance (calculation step) Four separate cases are distinguished: between two sequential points. Test runs performed If k, l, m > 0, then the point lies outside the triangle; internally have shown that for a 5 m calculation step
If k, l < 0 and m > 0, then: if (yM − yBC)(yM − yAB) and for approximately 70,000~80,000 triangles < 0, then the point lies inside the triangle, otherwise, describing the digital road surface and the terrain, the the point lies outside the triangle; required SSD adequacy investigation, regarding
If l, m < 0 and k > 0, then: if (yM − yBC)(yM − yAC) modern desktop computers, is performed in < 0, then the point lies inside the triangle, otherwise, approximately 10~15 min.
Z X B(xB,yB,zB)
O(xO,yO,zO)
A(xA,yA,zA)
M(xM,yM,zM)
C(xC,yC,zC)
Y (a) (b) Fig. 4 (a) Line-plane intersection; (b) intersection point inside triangle boundary.
Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation 239
Plan view
Longitudinal profile
Cross-sections Initial speed
Road environment SSDdemanded definition Driver position (i)
Digital terrain model 3-D road environment
Calc. step definition i Driver-object heights
SSD Driver’s line of sight until available definition position i uninterrupted i = i − Δi Driver’s line of sight until position i interrupted
SSDi available temp. definition SSDdemanded ≤ SSDavailable ΟΚ SSDdemanded > SSDavailable problem i = i + Δi Record position
Fig. 5 Flowchart of SSD adequacy investigation.
The credibility of H12 software in defining the (Fig. 6a).
SSDavailable was validated against an existing road The two utilized cross-sections (open roadway and section lacking SSD adequacy, which was surveyed via tunnel) are shown through Fig. 6b where certain details laser scanner [23]. The available SSD values, extracted found in RAA (German Freeway Design Guidelines) graphically utilizing appropriate market software [24], [2] should be emphasized: were correlated next to the relevant SSD values The inner shoulder width was considered 0.75 m extracted from H12, where a complete match was in open roadway areas and 0.50 m inside tunnels (in the found. latter case the tunnel inner walls were assumed vertical); 4. Case Study Driver’s eyes height as well as object height was In order to give a clear view of the H12 software both assumed 1.00 m, offset 1.80 m laterally from the SSD adequacy investigation outputs, the right branch inner side of the passing lane; of a hypothetical divided highway section of The Jersey barrier height was set to 0.90 m (0.81 approximately 4,300 m was designed according to the m plus safety margin), where the curvature at the top German Guidelines [2], assuming 120 km/h design increases the inner shoulder by 0.22 m. speed. The open roadway’s cross-section consists of a Furthermore, assuming that the project specifications Jersey barrier, two traffic lanes, the passing lane, which impose an advisory speed of 100 km/h, at the entering was selected to examine SSD provision, and an portal area, the effective length of the tunnel (length emergency lane. Due to the steep landscape, a tunnel of along which the advisory speed of 100 km/h is enforced) 1,250 m is proposed between St.3+000 and St.4+250 was inserted as well, consisting of the following:
240 Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation
(a)
Driver’s eye Driver’s eye
(b) Fig. 6 (a) Horizontal alignment; (b) cross-sections utilized (units in m).
300 m section in advance of the entering portal; alignment, where three different types of SSDs are extra 200 m segment ahead as a transition zone shown. The blue line refers to the demanded SSD, where the vehicle speed of 120 km/h is transitioned to where the green line denotes the available SSD, based 100 km/h. on roadway’s longitudinal profile (2-D assessment). Finally, since the adopted deceleration rate of 3.7 The objective of the present methodology is not m/s2 by RAA [2] corresponds to wet road surface limited in simply defining SSD shortage areas, since a conditions, in order to incorporate realistic emergency direct overview regarding the design elements that braking situations, dry pavement was assumed beyond restrict the driver’s vision is offered as well. For this a 300 m section inside the tunnel structure where the reason, the multi-colored 3-D available SSD line, conservative braking friction value of 0.65 which in general offers less sight distance compared to 2 (decelerationdry = 0.65 × 9.81 m/s ) was assumed. the relevant 2-D green line, is colored either purple, red, The roadway’s longitudinal, as well as linearly yellow or pink, based on whether the side road projected horizontal, profiles are shown in Fig. 7b. The formations and/or cut slopes, the roadway surface, the SSD adequacy investigation (Fig. 7a) is formed by a Jersey barrier or the tunnel lateral walls, “hide” the horizontal and two vertical axes. The horizontal axis obstacle from the driver, respectively. represents the road stations where the right vertical axis A closer look at Fig. 7 reveals two different under shows the vehicle’s advisory initial speed values along design zones, located at the areas where the blue line the roadway, based on the above assumptions. The left (SSDdemanded) overlaps the actual available SSD vertical axis illustrates various SSD values (multi-colored line). In terms of quantifying the SSD corresponding to the stations of the utilized compound safety violation area between the SSDdemanded and the
Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation 241
Horizon Road level
Ground altitude Station 0+000 Grades/distances
Horizontal alignment T = 621.44
Fig. 7 Roadway’s longitudinal profile and SSD adequacy investigation (unit in meters).
SSDavailable (3-D), the total SSD1 shortage zone is St.3+070). As a result, in the above unsuccessful approximately 1,280 m (area between St.0+520 and horizontal-vertical arrangement, the Jersey barrier and St.1+800), where the relevant SSD2 shortage zone is the tunnel lateral walls are responsible for the delivered approximately 175 m (area between St.2+895 and SSD1and SSD2 shortage areas, respectively.
242 Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation
5. Conclusions perception of reaction time, etc.) refer to daylight driving conditions, as, on the one hand, the vehicle The present paper describes a SSD adequacy speed values in night time driving conditions are 6~15 investigation resulting from any combination of design km/h less [25] and, on the other hand, the road view elements and based on the difference between the geometry changes. available and the demanded SSD. SSDdemanded, on one Finally, it should not be ignored that the human hand, is defined by utilizing the point mass model, factor, including perception-reaction procedure and the introduced by many design guidelines worldwide, and friction reserve utilized in the lateral direction during enriched by the actual values of grade and friction the braking process, might impose additional variation due to the effect of vertical curves and vehicle restrictions and, consequently, influence the braking cornering, respectively. On the other hand, the process to some extent. SSDavailable is described as the driver’s line of sight towards the object height at a certain offset in 3-D References roadway environment. [1] AASHTO (American Association of State Highway and The proposed methodology can accurately perform Transportation Officials). 2011. A Policy on Geometric SSD adequacy investigation in any 3-D road Design of Highways and Streets. Washington, DC: environment given that the ground, road and roadside AASHTO. [2] German Road and Transportation Research Association, elements are inserted. SSD shortage issues are created Committee, Geometric Design Standards. 2008. in roadway areas where the vision lines between driver Guidelines for the Design of Freeways. Germany: and obstacle are less than the relevant demanded RAΑ. [3] Ministeriode Fomento (Ministeriode Development). 2001. distances that safely route a vehicle to stop. Instrucción de Carreteras, Norma 3.1–IC “Trazado” Furthermore, H12 software provides flexibility (Spanish Road Design Guidelines). Spain: Ministeriode among every road design and/or vehicle dynamic Development. parameter inserted (e.g., lateral positioning of both [4] Ministry of Environment, Regional Planning and Public Works. 2001. Guidelines for the Design of Road Projects, driver and obstacle, vehicle speed and friction Part 3, Alignment (OMOE-X (Greek Road Design variations (tunnel areas of freeways where pavement is Guidelines)). Greece: Ministry of Environment, Regional considered dry)) as well as direct overview regarding Planning and Public Works. design elements responsible for SSD inadequacies. As [5] NTUA. 2012. H12, Road Design Software. Greece: NTUA. a result, precious guidance is provided to the designer [6] Hassan, Y., Easa, S. M., and Abd El Halim, A. O. 1997. for further alignment improvement but mostly an “Design Considerations for Combined Highway accurate aid to implement geometric design control Alignments.” Journal of Transportation Engineering 123 criteria with respect to both existing and new road (1): 60-8. [7] Sanchez, E. 1994. “Three-Dimensional Analysis of Sight sections is delivered. Distance on Interchange Connectors.” In Transportation The present software is, nowadays, used for Research Record 1445, 101-8. educational purposes in undergraduate classes at the [8] Hassan, Y., Easa, S. M., and Abd El Halim, A. O. 1996. “Analytical Model for Sight Distance Analysis on Department of Transportation Planning and Three-Dimensional Highway Alignments.” Engineering of Civil Engineering School in NTUA, Transportation Research Record 1523 (1): 1-10. where regarding the preparation of diploma theses, it is [9] Lovell, D. J., Jong, J. C., and Chang, P. C. 2001. considered to be an essential tool. Many highway “Improvement to the Sight Distance Algorithm.” Journal of Transportation Engineering 127 (4): 283-8. design and consultant firms in Greece use it as well. [10] Nehate, G., and Rys, M. 2006. “3-D Calculation of However, it is important to underline the fact that the Stopping-Sight Distance from GPS Data.” Journal of parameters used in the present paper (speed values, Transportation Engineering 132 (6): 691-8.
Analytical Method for 3-D Stopping Sight Distance Adequacy Investigation 243
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